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A1 adverb /wʌns/

Once

une fois seulement; autrefois
Meaning
one time only; at some time in the past; formerly
Example
I have been to Paris once in my life.
Je suis allé à Paris une fois dans ma vie.
C1 adjective /ˈɑp.ər.ə.tɪv/

Operative

actif; en vigueur; fonctionnant; opérationnel;
Meaning
Functioning; in effect; working; active;
Example
The new safety protocols became operative immediately after the accident.
Les nouveaux protocoles de sécurité sont devenus opérationnels immédiatement après l'accident.
A1 adverb /ɔːf/

off

éteint
Meaning
away from a place, position, or time; not functioning
Example
He turned off the light before leaving the room.
Il a éteint la lumière avant de quitter la pièce.
B2 noun /ˌɔː.ri.enˈteɪ.ʃən/

orientation

orientation
Meaning
the process of becoming familiar with a new situation or environment
Example
The company provides an orientation for all new employees.
L'entreprise offre une orientation à tous les nouveaux employés.
C2 adjective /əbˈstrɛpərəs/

obstreperous

tapageur et difficile à contrôler
Meaning
Noisy and difficult to control.
Example
The obstreperous students disrupted the class.
Les étudiants tapageurs ont perturbé le cours.
C2 verb /əˈkluːd/

occlude

obstruer
Meaning
To block or close up an opening or passage.
Example
The pipe was occluded by mineral deposits.
Le tuyau était obstrué par des dépôts minéraux.
C1 noun /ˈɔɪntmənt/

ointment

onguent
Meaning
A smooth, oily substance applied to the skin for healing or soothing.
Example
The doctor prescribed an ointment for the burn on his arm.
Le médecin a prescrit un onguent pour la brûlure sur son bras.
C1 noun /ˈɒstrəsɪzəm/

ostracism

ostracisme
Meaning
The act of excluding someone from a group or society.
Example
The student faced ostracism after breaking the rules.
L'étudiant a fait face à l'ostracisme après avoir enfreint les règles.
C1 noun /əbˈzɜːvəns/

observance

observance
Meaning
The practice of following a custom, rule, or religious law.
Example
The festival is held in observance of a centuries-old tradition.
Le festival est organisé en observance d'une tradition séculaire.
B2 noun /ˈaʊtˌskɜːrt/

outskirt

la périphérie de la ville
Meaning
the outer edge or border of a town or city
Example
They built a new factory on the outskirts of the city.
Ils ont construit une nouvelle usine en périphérie de la ville.
B2 noun /ˌɑb.zɚˈveɪ.ʃən/

Observation

observation
Meaning
the action of watching something carefully; a comment or remark
Example
The scientist made careful observations of the experiment.
Le scientifique a fait des observations minutieuses de l'expérience.
C2 adjective /ˈɔːrnəri/

ornery

irritable
Meaning
bad-tempered and combative; stubborn
Example
The ornery old man refused to leave his chair.
Le vieil homme irritable a refusé de quitter sa chaise.
A2 adjective /ɒd/

Odd

étrange; inhabituel; différent de ce qui est normal ou attendu
Meaning
strange; unusual; different from what is normal or expected
Example
That's an odd way to solve the problem.
C'est une façon étrange de résoudre le problème.
B2 adjective /ˈaʊtˌɡoʊɪŋ/

outgoing

sociable
Meaning
Friendly and sociable; inclined to mix with others.
Example
He is an outgoing person who loves meeting new people.
C'est une personne sociable qui aime rencontrer de nouvelles personnes.
C1 noun /ˈɒfʃuːt/

offshoot

dérivé
Meaning
A branch or result that develops from something larger or more important.
Example
The startup was an offshoot of a major tech company.
La startup était un dérivé d'une grande entreprise technologique.
C1 noun /ˈɔr.ə.kəl/

Oracle

oracle
Meaning
a person regarded as a source of wise counsel; in ancient times, a priest or priestess acting as a medium
Example
The ancient Greeks consulted the oracle at Delphi.
Les anciens Grecs consultaient l'oracle de Delphes.
A2 adverb; noun /ˌaʊtˈdɔːrz/

outdoors

à l’extérieur
Meaning
outside a building; the natural environment outside
Example
We spent the whole afternoon outdoors enjoying the fresh air.
Nous avons passé tout l’après-midi à l’extérieur à profiter de l’air frais.
C2 noun /əbˈsɪdiən/

obsidian

obsidienne (roche volcanique noire et vitreuse)
Meaning
A hard, dark, glasslike volcanic rock formed by rapid solidification of lava.
Example
The knife was made from sharp obsidian.
Le couteau était fabriqué à partir d'obsidienne tranchante.
B2 adjective, verb /əbˈskjʊr/

obscure

obscur
Meaning
Not clearly expressed or understood; to make something difficult to see or understand.
Example
The meaning of the poem was obscure to most readers.
La signification du poème était obscure pour la plupart des lecteurs.
B2 noun /ˈɔr.fən.ɪʒ/

Orphanage

orphelinat
Meaning
an institution for the care and education of children who have lost their parents
Example
The charity built a new orphanage for homeless children.
La charité a construit un nouvel orphelinat pour les enfants sans abri.
C1 adjective /ˈɒptɪməm/

optimum

optimal
Meaning
Most conducive to a favorable outcome; best.
Example
To achieve optimum results, we need to improve efficiency.
Pour obtenir des résultats optimaux, nous devons améliorer l'efficacité.
B2 noun /oʊk/

oak

chêne
Meaning
a large tree that produces acorns and has strong, hard wood
Example
The old oak tree provided shade for the entire yard.
Le vieux chêne a fourni de l'ombre à tout le jardin.
B2 verb əbˈzɜːrvd

observed

observer
Meaning
To celebrate or keep a religious or other festival.
Example
The day is observed annually to raise awareness.
Le jour est observé chaque année pour sensibiliser.
A2 adjective /ˈɔː.dɪ.nər.i/

Ordinary

ordinaire; normal; pas spécial
Meaning
normal; usual; not special
Example
It was just an ordinary day at the office.
C'était juste un jour ordinaire au bureau.
B2 noun /ˌoʊ.vɚˈkraʊ.dɪŋ/

overcrowding

surpeuplement excessif
Meaning
Excessive crowd or packed condition, having more people or vehicles in a place than the approved capacity.
Example
The subway system suffers from severe overcrowding during peak hours.
Le système de métro souffre de grave surpeuplement pendant les heures de pointe.
C2 verb /əbˈtruːd/

obtrude

intruser
Meaning
to force oneself or one's ideas into a situation uninvited or inappropriately
Example
He didn’t want to obtrude into their private conversation.
Il ne voulait pas intruser dans leur conversation privée.
C2 noun /əˈprəʊ.bri.əm/

opprobrium

opprobre, déshonneur
Meaning
Harsh criticism or public disgrace.
Example
The scandal brought opprobrium on the politician.
Le scandale a apporté l'opprobre au politicien.
C2 adjective /ˈɒfɪʃ/

offish

distant
Meaning
Unfriendly, distant, or reserved in manner.
Example
He seemed offish at the party and avoided most conversations.
Il semblait distant à la fête et évitait la plupart des conversations.
A1 adjective /oʊld/

old

vieux
Meaning
having lived for a long time; not new or young
Example
He still drives his old car.
Il conduit toujours sa vieille voiture.
B2 verb /ˌoʊvərˈloʊd/

overload

surcharger
Meaning
to load with too much weight or cargo; to give too much work or information
Example
Don't overload the washing machine or it might break down.
Ne surchargez pas la machine à laver sinon elle pourrait se casser.
C2 noun /əbˈstrʌkʃənɪst/

obstructionist

obstructionniste
Meaning
a person who deliberately delays or prevents progress by being uncooperative or oppositional
Example
The obstructionist in the committee kept delaying the decision-making process.
L'obstructionniste au sein du comite a continue a retarder le processus de prise de decision.
C1 verb /ˌaʊtˈweɪ/

outweigh

avoir plus de poids
Meaning
To be more important, valuable, or significant than something else.
Example
The benefits of the new policy outweigh the risks.
Les avantages de la nouvelle politique l'emportent sur les risques.
C2 verb /oʊˈpaɪn/

opine

exprimer une opinion
Meaning
to express an opinion or belief
Example
The professor opined that the policy would fail.
Le professeur a exprimé que la politique échouerait.
C1 adjective əʊˈpeɪk

opaque

opaque, impénétrable, difficile à comprendre
Meaning
Not able to be seen through; not transparent; difficult to understand.
Example
The glass was too opaque to see through.
Le verre était trop opaque pour voir à travers.
C1 adjective /əˈblaɪdʒɪŋ/

obliging

serviable
Meaning
Willing to help or do favors; accommodating.
Example
The staff at the hotel were very obliging and friendly.
Le personnel de l'hôtel était très serviable et amical.
C1 noun /əˈkɜr.əns/

Occurrence

événement
Meaning
an instance or event of something happening; the fact of occurring
Example
The occurrence of earthquakes is common in this region.
L'occurrence des tremblements de terre est courante dans cette région.
A2 noun /əˈlɪmpɪks/

olympics

Jeux Olympiques
Meaning
an international sports competition held every four years with athletes from many countries
Example
The Olympics bring athletes from all over the world together.
Les Jeux Olympiques réunissent des athlètes du monde entier.
C2 noun /ˈɒlɪv bɑːb/

Olive barb

barbe olive
Meaning
A small freshwater fish with olive-colored body and barbels
Example
The olive barb is commonly found in South Asian rivers.
La barbe olive se trouve couramment dans les rivières d’Asie du Sud.
B1 noun /ˈɒbstəkəlz/

obstacles

obstacles
Meaning
Things that block one's way or prevent or hinder progress.
Example
Obstacles in life can often lead to valuable lessons.
Les obstacles dans la vie mènent souvent à des leçons précieuses.
A2 adjective /ˈɒb.vi.əs/

Obvious

évident; facile à comprendre
Meaning
easily perceived or understood; clear and apparent to the mind
Example
It was obvious that she was upset about something.
Il était évident qu'elle était contrariée à propos de quelque chose.
C2 noun /ˌɑːpərˈtuːnɪzəm/

opportunism

opportunisme
Meaning
The practice of taking advantage of opportunities regardless of principles or ethics.
Example
His decision was driven by opportunism, not values.
Sa décision a été motivée par l'opportunisme, pas par des valeurs.
C1 verb ˈɔːr.kɪ.streɪt

orchestrate

orchestrer
Meaning
To plan or coordinate the elements of (a situation) to produce a desired effect, especially surreptitiously.
Example
He skillfully orchestrated the entire event.
Il a habilement orchestré l'ensemble de l'événement.
C1 noun ˌoʊ.vɚˈɡreɪ.zɪŋ

overgrazing

surpâturage
Meaning
The practice of allowing livestock to graze to the point of damaging vegetation.
Example
Overgrazing leads to soil erosion and loss of biodiversity.
Le surpâturage conduit à l'érosion des sols et à la perte de biodiversité.
C1 adjective /ɒˈstɛnsəbl/

ostensible

apparente
Meaning
stated or appearing to be true, but not necessarily so
Example
His ostensible reason for leaving was illness, but many doubted it.
Sa raison apparente de partir était la maladie, mais beaucoup en doutaient.
C1 noun ˈaʊt.sɔːr.sɪŋ

outsourcing

externalisation
Meaning
The practice of having certain job functions done outside a company instead of having an in-house department or employee handle them.
Example
Many companies use outsourcing to reduce labor costs.
De nombreuses entreprises utilisent l'externalisation pour réduire les coûts de main-d'œuvre.
C1 adjective /ˈəʊnərəs/

onerous

ardu
Meaning
involving a great deal of effort, difficulty, or burden
Example
Fulfilling the contract proved to be an onerous task for the company.
Accomplir le contrat s'est avéré être une tâche ardue pour l'entreprise.
B2 adjective; verb (past participle) /ˈɒkjʊpaɪd/

occupied

occupé
Meaning
being in use or taken; filled or lived in; controlled or held by force
Example
The room is occupied, so please wait outside.
La chambre est occupée, veuillez attendre dehors.
C1 adjective /əˈkʌlt/

occult

occultes
Meaning
Relating to mysterious, supernatural, or magical powers and practices.
Example
She had always been fascinated by the occult and its hidden knowledge.
Elle a toujours été fascinée par l'occulte et sa connaissance cachée.
C1 adjective ˈɒptɪmaɪzd

optimized

optimisé, amélioré, plus efficace
Meaning
Made as fully perfect, functional, or effective as possible; improved to achieve maximum efficiency.
Example
The system has been optimized for faster performance.
Le système a été optimisé pour des performances plus rapides.
C1 adjective /ˈɔːrθədɑːks/

orthodox

orthodoxe
Meaning
conforming to traditional beliefs or practices
Example
He comes from a very orthodox family.
Il vient d'une famille très orthodoxe.
B2 noun /ˈɔːrnəmənt/

ornament

ornement
Meaning
A decorative object that adds beauty to something.
Example
The Christmas tree was decorated with colorful ornaments.
L'arbre de Noël était décoré avec des ornements colorés.
A2 noun /ˈɒpərə/

opera

opéra
Meaning
a dramatic performance in which the actors sing most of their lines
Example
We watched a beautiful opera at the theater last night.
Nous avons regardé un bel opéra au théâtre hier soir.
C2 adjective /ˌoʊpəˈlɛsənt/

opalescent

opalescent
Meaning
showing or reflecting a milky, iridescent light like an opal
Example
The opalescent sky glowed with shades of pink and blue.
Le ciel opalescent brillait avec des nuances de rose et de bleu.
C2 adjective /əˈfɪʃəs/

officious

médicule
Meaning
Excessively eager to offer unwanted help or advice; meddlesome.
Example
The officious guard kept interrupting the visitors with unnecessary instructions.
Le garde médicule interrompait les visiteurs avec des instructions inutiles.
C1 verb /ˌoʊvərˈθroʊ/

overthrow

bonheur
Meaning
To remove a leader or government from power, often by force.
Example
The rebels planned to overthrow the corrupt regime.
Elle ne pouvait pas cacher son bonheur lorsqu'elle a reçu le prix.
C2 adjective /ɔːrˈθɑːɡənl/

orthogonal

orthogonal
Meaning
at right angles; independent or unrelated
Example
In mathematics, two vectors are orthogonal if their dot product is zero.
En mathématiques, deux vecteurs sont orthogonaux si leur produit scalaire est nul.
B2 noun ˈəʊnəʃɪp

ownership

propriété
Meaning
The act, state, or right of possessing something; legal title to something.
Example
Ownership of resources was crucial.
La propriété des ressources était cruciale.
C1 verb /əbˈstrʌkt/

obstruct

obstruer
Meaning
to block or hinder progress; to prevent or impede movement
Example
The fallen tree obstructed the road for several hours.
L'arbre tombé obstruait la route pendant plusieurs heures.
A1 conjunction /ɔːr/

or

ou
Meaning
used to link alternatives
Example
You can have tea or coffee.
Vous pouvez prendre du thé ou du café.
C2 noun /əbˈstɛtrɪks/

obstetrics

obstétrique
Meaning
The branch of medicine dealing with childbirth and care of women giving birth.
Example
She is studying obstetrics to become a specialist in childbirth.
Elle étudie l'obstétrique pour devenir spécialiste de l'accouchement.
B2 verb /əˈpoʊz/

oppose

s'opposer
Meaning
to disagree with or resist; to act against
Example
Many citizens oppose the new tax policy.
Beaucoup de citoyens s'opposent à la nouvelle politique fiscale.
A1 adverb /ˈɔːfən/

often

souvent
Meaning
frequently, many times
Example
I often visit my grandparents on weekends.
Je visite souvent mes grands-parents le week-end.
C2 noun /ɒmˈnɪʃəns/

omniscience

omniscience
Meaning
the state of knowing everything
Example
The novel's narrator has an air of omniscience, revealing every character's thoughts.
Le narrateur du roman a un air d'omniscience, révélant les pensées de chaque personnage.
B1 noun ˈɒk.sɪ.dʒən

oxygen

oxygène. Un gaz incolore et inodore, essentiel pour la vie.
Meaning
A colorless, odorless reactive gas, the chemical element of atomic number 8 and the life-supporting component of the air.
Example
Oxygen is vital for life.
L'oxygène est vital pour la vie.
B2 noun /ɑːks/

Ox

bœuf
Meaning
a large strong animal used for pulling heavy loads or plowing fields
Example
The farmer used an ox to plow the field.
L'agriculteur a utilisé un bœuf pour labourer le champ.
B2 noun ˈaʊt.pʊt

output

production
Meaning
The amount of something produced by a person, machine, or industry.
Example
Climate change reduces agricultural output.
Le changement climatique réduit la production agricole.
B2 adjective /ˈɒp.ʃən.əl/

Optional

facultatif
Meaning
not compulsory; left to choice
Example
Wearing a tie is optional for this event.
Porter une cravate est facultatif pour cet événement.
C2 adjective /ɒmˈnɪʃ.ənt/

Omniscient

omniscient
Meaning
having complete knowledge; all-knowing
Example
The narrator in the novel appears to be omniscient, knowing every character's thoughts.
Le narrateur dans le roman semble être omniscient, connaissant toutes les pensées des personnages.
B2 adjective /ˌfæʃ.ənd/

Outdated

obsolète
Meaning
obsolete; no longer current
Example
This computer software is completely outdated.
Ce logiciel informatique est complètement obsolète.
C1 verb /ˈɒp.tɪ.maɪz/

optimize

optimiser
Meaning
To make the best or most effective use of a situation, opportunity, or resource.
Example
The company is working to optimize its supply chain.
L'entreprise travaille à optimiser sa chaîne d'approvisionnement.
C1 adjective /ˈɒm.ɪ.nəs/

Ominous

menaçant; sinistre
Meaning
giving the impression that something bad will happen; threatening; foreboding
Example
The dark clouds looked ominous before the storm.
Les nuages sombres paraissaient menaçants avant la tempête.
B2 verb /ˌoʊvərˈduː/

overdo

exagérer
Meaning
to do something too much; to exaggerate or carry to excess
Example
Don't overdo the exercise on your first day at the gym.
Ne fais pas trop d'exercice le premier jour à la salle de sport.
C2 noun /ˌɔːrnɪˈθɑːlədʒi/

ornithology

ornithologie
Meaning
the scientific study of birds
Example
She pursued ornithology to understand the migration patterns of birds.
Elle a poursuivi l'ornithologie pour comprendre les schémas de migration des oiseaux.
C2 noun /ˈɒkjʊlɪst/

oculist

ophtalmologiste
Meaning
An old-fashioned term for an eye doctor or ophthalmologist.
Example
The village oculist was known for treating various eye diseases.
L'oculiste du village était connu pour traiter diverses maladies des yeux.
B1 noun /aʊl/

Owl

hibou
Meaning
a nocturnal bird of prey with large eyes and a hooked beak
Example
The owl hooted softly in the darkness of the forest.
Le hibou hululait doucement dans l'obscurité de la forêt.
C1 noun /ˈɒktɪv/

octave

octave
Meaning
A series of eight musical notes, or the interval between one musical pitch and another with double its frequency.
Example
The singer's voice could easily reach the higher octave.
La voix du chanteur pourrait facilement atteindre l'octave supérieure.
B2 adjective /ˈɔɪl.i/

Oily

huileux; recouvert d'huile; gras
Meaning
covered with oil; containing oil; greasy
Example
Her oily skin needs special care.
Sa peau huileuse a besoin de soins spéciaux.
C1 noun /əˈpreʃ.ən/

Oppression

oppression; abus; tyrannie;
Meaning
cruel or unjust treatment or exercise of authority; the state of being subject to harsh treatment
Example
The people fought against political oppression.
Les gens ont lutté contre l'oppression politique.
C2 noun /oʊf/

Oaf

une personne maladroite, stupide ou insensible
Meaning
a clumsy, stupid, or insensitive person
Example
Don't be such an oaf - handle the dishes carefully!
Ne sois pas un oaf - manipule les plats avec soin !
C2 verb /ˌoʊvərˈliːp/

overleap

sauter par-dessus
Meaning
To jump over something; to omit or disregard something.
Example
He managed to overleap the fence easily.
Il a réussi à sauter la clôture facilement.
B2 noun ˈɔː.bɪt

orbit

orbite
Meaning
The curved path of a celestial object around a star, planet, or moon.
Example
The satellite maintains its orbit around Earth.
Le satellite maintient son orbite autour de la Terre.
A2 adjective/adverb /ˈɒnˌlaɪn/

online

en ligne
Meaning
connected to or available through the internet
Example
I prefer shopping online rather than going to stores.
Je préfère faire du shopping en ligne plutôt que d'aller dans les magasins.
C2 adjective /ˌoʊvərˈwiːnɪŋ/

overweening

arrogant excessif
Meaning
excessively arrogant or prideful
Example
His overweening pride cost him many friends.
Son excès de fierté lui a coûté de nombreux amis.
C2 noun /ɔːrˈθɑːɡrəfi/

orthography

orthographe
Meaning
The conventional spelling system of a language.
Example
English orthography can be confusing for learners.
L'orthographe anglaise peut être déroutante pour les apprenants.
C1 adjective /əbˈstrʌk.tɪv/

Obstructive

obstructif
Meaning
deliberately creating difficulties or preventing progress; hindering or blocking something
Example
The obstructive policies hindered economic growth.
Les politiques obstructives ont entravé la croissance économique.
B2 noun /ˌɑb.lɪˈɡeɪ.ʃən/

Obligation

obligation
Meaning
a duty or commitment; something that must be done legally or morally
Example
Parents have an obligation to care for their children.
Les parents ont l'obligation de prendre soin de leurs enfants.
B2 noun /ˈaʊtskɜːrts/

outskirts

périphérie de la ville
Meaning
The outer parts of a town or city, away from the center.
Example
They moved to the outskirts of the city for a quieter life.
Ils ont déménagé en périphérie de la ville pour une vie plus calme.
B2 noun /əbˈdʒek.ʃən/

Objection

objection; désaccord; protestation;
Meaning
an expression of disagreement or disapproval; a reason for disagreeing
Example
The lawyer raised an objection during the trial.
L'avocat a soulevé une objection pendant le procès.
B1 verb /əbˈzɜːrv/

observe

observer
Meaning
to watch carefully; to notice or perceive something
Example
Scientists observe the behavior of animals in the wild.
Les scientifiques observent le comportement des animaux dans la nature.
C1 adjective /ˌaʊt əv ðə ˈweɪ/

out-of-the-way

éloigné ou inhabituel
Meaning
remote or unusual; not in a convenient or usual location
Example
They stayed in an out-of-the-way village.
Ils sont restés dans un village éloigné.
B2 adjective /ˈɒp.tɪ.məl/

optimal

optimal, le plus favorable
Meaning
Best or most favorable; the most effective under particular conditions.
Example
The optimal temperature for plant growth is around 25°C.
La température optimale pour la croissance des plantes est d'environ 25°C.
A2 noun /ˈɒm.lət/

Omelet

omelette
Meaning
a dish made from beaten eggs cooked in a frying pan and often folded around a filling
Example
She made a cheese omelet for breakfast.
Elle a préparé une omelette au fromage pour le petit déjeuner.
C2 noun ˌɒbfəsˈkeɪʃən

obfuscation

obfuscation, confusion
Meaning
The action of making something obscure, unclear, or unintelligible.
Example
The obfuscation of the data made it difficult to interpret.
L'obfuscation des données a rendu leur interprétation difficile.
C1 adjective /ˌɔː.riˈen.təl/

Oriental

relatif aux pays de l'Asie de l'Est; oriental
Meaning
relating to the countries of East Asia; eastern
Example
The museum has a beautiful collection of oriental art.
Le musée possède une belle collection d'art oriental.
C2 verb /əbˈvɜːrt/

obvert

inverser
Meaning
To turn something so as to face in a different direction; in logic, to convert a proposition by negating both subject and predicate.
Example
The teacher asked the students to obvert the statement for practice.
Le professeur a demandé aux étudiants de convertir la déclaration pour s'exercer.
C1 noun /ˈɑːdəsi/

odyssey

long voyage
Meaning
a long, adventurous journey; a series of experiences
Example
Her career has been an odyssey of challenges and achievements.
Sa carrière a été une odyssée de défis et de réussites.
C1 noun /ˈɒn.slɔːt/

onslaught

assaut
Meaning
A fierce or destructive attack.
Example
The village faced an onslaught of enemy forces.
Le village a fait face à un assaut des forces ennemies.
B2 noun /ˈaʊt.breɪk/

Out-break

épidémie
Meaning
a sudden occurrence or eruption of something, especially disease or violence
Example
The outbreak of flu affected many students in the school.
L'épidémie de grippe a touché de nombreux élèves à l'école.
C2 noun /ˈɒfərtɔːri/

offertory

offrande
Meaning
The part of a religious service when offerings are collected; the offering itself.
Example
The offertory was taken during the Sunday service.
L'offrande a été prise pendant le service du dimanche.
C2 noun /ˈoʊvərlɔːrd/

overlord

seigneur
Meaning
A ruler, master, or person of great power and authority over others.
Example
The peasants were forced to pay taxes to their overlord.
Les paysans ont été forcés de payer des impôts à leur seigneur.
B2 noun /ˈɑp.tə.mɪst/

Optimist

optimiste
Meaning
a person who tends to be hopeful and confident about the future; someone who sees the good side of things
Example
As an optimist, she always believed things would improve.
En tant qu'optimiste, elle a toujours cru que les choses s'amélioreraient.
C1 verb əˈblɪt.ə.reɪt

obliterate

anéantir
Meaning
To destroy utterly; wipe out completely, to erase or remove something completely.
Example
The storm obliterated entire villages.
La tempête a anéanti des villages entiers.
A1 noun/adjective/adverb /ˌaʊtˈsaɪd/

outside

dehors
Meaning
the external part or surface of something; beyond the boundary
Example
Children were playing outside in the yard.
Les enfants jouaient dehors dans le jardin.
C2 noun /ˈɔːrɪndʒfɪn ˈleɪbiːoʊ/

Orangefin labeo

labeo à nageoires orange
Meaning
a freshwater fish species native to South Asian rivers, commonly found in Bangladesh and India
Example
The orangefin labeo is an important food fish in Bangladesh.
Le labeo à nageoires orange est un poisson alimentaire important au Bangladesh.
A2 modal verb /ɔːt/

ought

devrait
Meaning
Used to indicate duty, correctness, or moral obligation.
Example
You ought to respect your elders.
Tu devrais respecter tes aînés.
B2 adjective /aʊtˈreɪdʒəs/

outrageous

scandaleux
Meaning
Shockingly bad or excessive; very unusual or amusing.
Example
The comedian told an outrageous joke.
Le comédien a raconté une blague scandaleuse.
C2 noun /ˈoʊpiət/

opiate

opiacé
Meaning
a drug containing opium or its derivatives, used to relieve pain or cause sleep
Example
The doctor prescribed an opiate to relieve the patient's pain.
Le docteur a prescrit un opiacé pour soulager la douleur du patient.
C1 noun /ɒpˈtɒmɪtrɪst/

optometrist

optométriste
Meaning
A healthcare professional who examines eyes and prescribes corrective lenses.
Example
The optometrist prescribed new glasses for her.
L'optométriste a prescrit de nouvelles lunettes pour elle.
C2 noun /ɑːlˈfækʃən/

olfaction

olfaction
Meaning
The sense of smell; the process of detecting and perceiving odors.
Example
Dogs have a highly developed sense of olfaction.
Les chiens ont un sens de l'olfaction très développé.
C2 noun /ˈɔːrdʒi/

orgy

orgie
Meaning
A wild party involving excessive indulgence, especially of a sexual nature.
Example
The novel described a scandalous orgy in a wealthy mansion.
Le roman a décrit une orgie scandaleuse dans un manoir riche.
B2 adjective /ˌɑːp.təˈmɪs.tɪk/

optimistic

optimiste
Meaning
hopeful and confident about the future
Example
She is optimistic about the success of her new project.
Elle est optimiste quant au succès de son nouveau projet.
B2 noun /əˈfens/

Offence

offense; délit; attaque
Meaning
a breach of law or rule; an annoyance or resentment
Example
Stealing is a serious offence punishable by law.
Le vol est une offense grave punissable par la loi.
C2 noun /ˈɒb.stɪ.nə.si/

obstinacy

obstination
Meaning
Stubborn refusal to change one's opinion or chosen course of action, despite attempts to persuade one to do so.
Example
His obstinacy made negotiations difficult.
Son obstination a rendu les négociations difficiles.
B1 noun /ˈɑː.lɪv/

Olive

olive
Meaning
a small oval fruit with a hard pit, typically green or black, used for eating or making oil
Example
Olive oil is considered one of the healthiest cooking oils available.
L'huile d'olive est considérée comme l'une des huiles de cuisson les plus saines disponibles.
B2 noun /ˈɒpəreɪtər/

operator

opérateur
Meaning
a person who operates equipment, a business, or controls something
Example
The machine operator ensured that everything ran smoothly.
L'opérateur de la machine s'est assuré que tout fonctionnait correctement.
B2 verb /ˌoʊvərˈlʊk/

overlook

ignorer
Meaning
to fail to notice or consider something; to have a view from above
Example
It's easy to overlook small details when you're in a hurry.
Il est facile de passer à côté des petits détails quand on est pressé.
B2 adjective + noun ˈɒptɪməl ˈtempərətʃər

optimal temperature

température optimale
Meaning
The best or most favorable temperature for a particular purpose
Example
Winter provides optimal temperature for farming.
L'hiver fournit la température optimale pour l'agriculture.
C1 verb /ˈoʊvərˌhɔːl/

overhaul

révision complète
Meaning
to examine thoroughly and repair or improve something that is worn or ineffective
Example
The company decided to overhaul its outdated computer system.
L'entreprise a décidé de rénover son système informatique obsolète.
A1 adjective /əʊˈkeɪ/

okay

d'accord
Meaning
used to express agreement or acceptance
Example
It's okay to leave early today.
Il est d'accord de partir tôt aujourd'hui.
C1 noun /ˈaʊtpoʊst/

outpost

avant-poste
Meaning
A small military camp or position at some distance from the main force, used especially as a guard.
Example
The soldiers were stationed at a remote outpost.
Les soldats étaient stationnés dans un avant-poste éloigné.
C2 noun /ˈɔː.rɪ.fɪs/

orifice

orifice
Meaning
an opening or hole, especially in the body or a device
Example
The medicine was applied through a small orifice in the device.
Le médicament a été appliqué par un petit orifice dans l'appareil.