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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.
C2 noun /ɔːˈreɪʃən/

oration

discours
Meaning
A formal speech, especially one given on a ceremonial occasion
Example
The president delivered an inspiring oration.
Le président a prononcé un discours inspirant.
B1 noun ˌɔː.ɡən.aɪˈzeɪ.ʃənz

organizations

organisations
Meaning
Organized groups of people with a particular purpose
Example
Organizations play a key role in policymaking.
Les organisations jouent un rôle clé dans l'élaboration des politiques.
C1 adjective ˈɒk.sɪ.də.tɪv

oxidative

Relatif à l'oxydation
Meaning
Related to or caused by oxidation, especially cellular damage from free radicals.
Example
Excess stress can lead to oxidative damage in cells.
Le stress excessif peut entraîner des dommages oxydatifs dans les cellules.
B2 noun ɔːˈɡæn.ɪk fuːdz

organic foods

aliments biologiques
Meaning
Food produced without the use of chemicals such as artificial pesticides, fertilizers, or other artificial agents.
Example
Organic foods are healthier than processed foods.
Les aliments biologiques sont plus sains que les aliments transformés.
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.
A1 pronoun, noun, adjective /wʌn/

one

un
Meaning
the number equivalent to the sum of zero and one; a single person or thing
Example
Only one student answered the question.
Un seul étudiant a répondu à la question.
A2 adjective /əˈlɪmpɪk/

olympic

olympique
Meaning
related to the Olympic Games, a major international sporting event
Example
She trained hard to compete in the Olympic Games.
Elle a beaucoup travaillé pour participer aux Jeux Olympiques.
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.
C2 noun /ˈɒlɪv brɑːntʃ/

olive-branch

branche d'olivier
Meaning
A symbol of peace or reconciliation; an offer to end conflict.
Example
He extended an olive-branch to his rival after years of hostility.
Il a tendu une branche d'olivier à son rival après des années d'hostilité.
C1 noun /ˈɑːlɪˌɡɑːrki/

oligarchy

oligarchie
Meaning
A small group of people having control of a country, organization, or institution.
Example
The nation was ruled by a wealthy oligarchy that controlled all resources.
La nation était dirigée par une oligarchie riche qui contrôlait toutes les ressources.
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.
C1 verb /ˌoʊvərˈʃædoʊ/

overshadow

éclipser
Meaning
to appear more important or significant than something else, reducing its impact
Example
The scandal overshadowed his achievements.
Le scandale a éclipsé ses réalisations.
B2 noun /əbˈsɛʃən/

obsession

obsession
Meaning
An idea, thought, or concern that continually preoccupies or intrudes on a person's mind.
Example
His obsession with success drove him to work day and night.
Son obsession pour le succès l'a poussé à travailler jour et nuit.
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 /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.
A2 preposition /ˈɒntu/

onto

sur
Meaning
moving to a position on the surface of something
Example
She jumped onto the table to get the book.
Elle a sauté sur la table pour prendre le livre.
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.
C1 verb /aʊtˈlæst/

outlast

durer plus longtemps que
Meaning
to continue longer than; to endure beyond someone or something else
Example
The old castle has outlasted many generations.
Le vieux château a duré plus longtemps que de nombreuses générations.
C1 verb /ˌoʊvərˈruːl/

overrule

rejeter
Meaning
to reject or disallow by exercising one's superior authority; to override a decision
Example
The judge overruled the objection from the defense attorney.
Le juge a rejeté l'objection de l'avocat de la défense.
C1 adjective /ˌəʊ.vərˈɑː.tʃɪŋ/

overarching

global, englobant, tout-en-un
Meaning
Comprehensive or all-embracing; forming an arch over something.
Example
The overarching theme of the book is human resilience.
Le thème global du livre est la résilience humaine.
A2 noun əˈlɪm.pɪk ɡeɪmz

Olympic Games

jeux olympiques
Meaning
The world's largest international sports competition held every four years, bringing together athletes from different countries to compete in various sports.
Example
The Olympic Games bring together the world's top athletes.
Les Jeux Olympiques réunissent les meilleurs athlètes du monde.
B1 noun /ˈɑb.stə.kəl/

Obstacle

obstacle
Meaning
something that blocks or makes progress difficult; a barrier
Example
Bad weather was the main obstacle to our journey.
Le mauvais temps était le principal obstacle à notre voyage.
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 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 /ˈɔr.fən/

Orphan

orphelin
Meaning
a child whose parents are dead; someone without protective support
Example
The orphan was adopted by a loving family.
L'orphelin a été adopté par une famille aimante.
C1 noun /ˈoʊvərˌtʊr/

overture

ouverture / proposition
Meaning
An introduction to something more substantial; a proposal or preliminary action.
Example
The peace overture was welcomed by both nations.
L'ouverture de la paix a été accueillie favorablement par les deux nations.
B1 verb /ˈɒpəreɪt/

operate

fonctionner
Meaning
to function; to control or manage; to perform surgery
Example
The surgeon will operate on the patient tomorrow.
Le chirurgien opérera le patient demain.
C1 noun ˈoʊʃən əˌsɪdɪfɪˈkeɪʃən

ocean acidification

acidification océanique
Meaning
The ongoing decrease in the pH of the Earth's oceans, caused by the absorption of carbon dioxide from the atmosphere.
Example
Ocean acidification is caused by atmospheric CO2 absorption.
L'acidification océanique est causée par l'absorption du CO2 atmosphérique.
B2 verb /oʊˈmɪt/

omit

omettre
Meaning
to leave out or exclude; to fail to include something
Example
Please don't omit any important details from your report.
Veuillez ne pas omettre les détails importants dans votre rapport.
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.
C1 noun /ˈəʊ.nəs/

onus

responsabilité
Meaning
A duty or responsibility, especially a heavy one.
Example
The onus is on the government to provide relief to the victims.
La responsabilité incombe au gouvernement de fournir de l'aide aux victimes.
C1 verb /aʊtˈlɪv/

outlive

survivre
Meaning
to live longer than someone or something else
Example
She outlived all her siblings.
Elle a vécu plus longtemps que tous ses frères et sœurs.
C2 adjective /ˌɔːfˈkiː/

off-key

fausse note
Meaning
out of tune; not in accordance with expected standards
Example
The singer was slightly off-key during the performance.
Le chanteur était légèrement hors de ton pendant la performance.
B2 noun /ˈoʊ.vər ɡroʊθ/

Over growth

surcroissance
Meaning
excessive growth beyond normal size; too much development or expansion
Example
The overgrowth of weeds made the garden look untidy.
La surcroissance des mauvaises herbes a rendu le jardin désordonné.
C1 verb /əˈfɪʃieɪt/

officiate

officier
Meaning
To perform official duties, especially in a ceremony or as a referee.
Example
The priest will officiate the wedding ceremony.
Le prêtre officiera la cérémonie de mariage.
C1 noun /əbˈstrʌkʃən/

obstruction

obstacle
Meaning
Something that blocks or gets in the way; the action of obstructing.
Example
There was an obstruction on the railway track.
Il y avait un obstacle sur la voie ferrée.
C2 noun /ˈɔːrzmən/

Oarsman

rameur
Meaning
a person who rows a boat, especially as a member of a racing crew
Example
The experienced oarsman rowed the boat across the river.
Le rameur expérimenté a ramé le bateau à travers le fleuve.
C1 adjective /ˌɒstɛnˈteɪʃəs/

ostentatious

ostentatoire
Meaning
Characterized by a showy or pretentious display intended to impress others.
Example
He wore an ostentatious gold chain to the party.
Il portait une chaîne en or ostentatoire à la fête.
A1 interjection /oʊ/

oh

Oh
Meaning
used to express surprise, realization, or understanding
Example
Oh, I didn't know you were here!
Oh, je ne savais pas que tu étais ici !
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.
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 adjective /ˈɒkjʊlər/

ocular

oculaire
Meaning
Relating to the eye or vision.
Example
The patient was referred to a specialist for ocular treatment.
Le patient a été orienté vers un spécialiste pour un traitement oculaire.
C2 noun /əˈblɪkwɪti/

obliquity

obliquité
Meaning
Deviation from moral or usual conduct; indirectness or lack of straightforwardness.
Example
The politician was criticized for the obliquity of his answers.
Le politicien a été critiqué pour l'obliquité de ses réponses.
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.
B1 adjective /əˈfɪʃəl/

official

officiel
Meaning
relating to or connected with an authority or public office
Example
He is the official spokesperson for the company.
Il est le porte-parole officiel de l'entreprise.
B2 noun /ɔːˈræŋ.ʊˌtæŋ/

Orang-Outang

orang-outang
Meaning
a large arboreal ape with long reddish hair, long arms, and hooked hands and feet, native to Borneo and Sumatra
Example
The orangutan swings gracefully through the forest canopy.
L'orang-outang se balance gracieusement à travers la canopée de la forêt.
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.
C1 noun /əˈfen.dər/

Offender

délinquant; infractionniste de la loi
Meaning
a person who commits an illegal act; someone who breaks the law
Example
The young offender was sentenced to community service.
Le jeune délinquant a été condamné à des travaux d'intérêt général.
C2 adjective /əbˈtruːsɪv/

obtrusive

intrusif
Meaning
noticeable in an unpleasant or unwelcome way; intrusive
Example
The advertisement was so obtrusive that it ruined the user’s experience.
La publicité était tellement intrusive qu'elle a ruiné l'expérience de l'utilisateur.
B2 noun /ˈɔːɡən/

organ

organe
Meaning
a part of the body that performs a specific function
Example
The heart is an important organ in the human body.
Le cœur est un organe important dans le corps humain.
C2 noun /ˈɒn.rʌʃ/

onrush

ruée
Meaning
A sudden powerful forward or downward rush or flow.
Example
The onrush of water swept away the bridge.
La ruée d'eau emporta le pont.
C2 noun /oʊˈbeɪsəns/

obeisance

révérence
Meaning
A gesture of respect such as a bow or curtsy.
Example
They bowed in obeisance to the king.
Ils se sont inclinés en révérence au roi.
B2 adjective /ˌɔːɡənaɪˈzeɪʃənəl/

organizational

organisationnel
Meaning
relating to the structure or arrangement of a company or group
Example
He works on improving the organizational structure of the company.
Il travaille à améliorer la structure organisationnelle de l'entreprise.
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.
C2 noun ˈɒpjʊləns

opulence

opulence
Meaning
Great wealth or luxuriousness.
Example
The opulence of the mansion was evident in its ornate furnishings.
L'opulence du manoir était évidente dans ses meubles ornés.
C1 noun /ˈɔːrdɪnəns/

ordinance

ordonnance
Meaning
An authoritative rule, law, or decree issued by a city, town, or authority.
Example
The city council passed an ordinance banning smoking in public parks.
Le conseil municipal a adopté une ordonnance interdisant de fumer dans les parcs publics.
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 adjective /ˌɑːpərˈtuːn/

opportune

moment opportun
Meaning
Happening at a suitable or convenient time.
Example
She arrived at an opportune moment to help.
Elle est arrivée à un moment opportun pour aider.
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 noun /ˈɔr.ə.tər/

Orator

orateur
Meaning
a public speaker, especially one who is eloquent or skilled in speaking
Example
The famous orator delivered an inspiring speech.
Le célèbre orateur a prononcé un discours inspirant.
C2 adjective /əˈprəʊ.bri.əs/

opprobrious

désobligeant
Meaning
Expressing strong criticism or scorn.
Example
He made opprobrious remarks about his opponent.
Il a fait des remarques désobligeantes sur son adversaire.
B2 noun /ˈɒkjʊpənt/

occupant

occupant
Meaning
A person who resides in or is present in a house, vehicle, seat, or place.
Example
The car had three occupants at the time of the accident.
La voiture avait trois occupants au moment de l'accident.
B2 adjective ɔːrˈɡæn.ɪk

organic

biologique
Meaning
Produced or involving production without the use of chemical fertilizers, pesticides, or other artificial agents.
Example
Organic farming improves soil health and reduces pollution.
L'agriculture biologique améliore la santé du sol et réduit la pollution.
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.
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.
B1 noun /ˌɒp.əˈtjuː.nə.ti/

opportunity

opportunité
Meaning
A favorable chance or set of circumstances that makes it possible to do something.
Example
She seized the opportunity to study abroad.
Elle a saisi l'opportunité d'étudier à l'étranger.
B2 verb /ˌoʊvərˈkʌm/

overcome

surmonter
Meaning
To succeed in dealing with a problem or difficulty.
Example
You can overcome procrastination with planning.
Vous pouvez surmonter la procrastination en planifiant.
C2 verb /ˌoʊvərˈstraɪd/

overstride

franchir en faisant de grands pas
Meaning
To stride over something; to step across with long steps.
Example
He managed to overstride the narrow stream with ease.
Il a réussi à franchir le ruisseau étroit avec facilité.
C1 adjective /əbˈzɜːrvənt/

Observant

observateur
Meaning
quick to notice things; watchful; attentive
Example
The observant detective noticed every small detail at the crime scene.
Le détective observateur a remarqué chaque petit détail sur la scène du crime.
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.
A2 noun /ˈoʊ.ʃən/

ocean

océan
Meaning
A very large expanse of sea, especially the main areas of sea between continents.
Example
The ocean covers more than 70% of the Earth's surface.
L'océan couvre plus de 70% de la surface de la Terre.
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.
B2 noun /ˈɔːkɪstrə/

orchestra

orchestre
Meaning
a large group of musicians playing different instruments together
Example
The orchestra performed beautifully at the concert.
L'orchestre a joué magnifiquement au concert.
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.
C2 verb /ˈɑːbdʒərˌɡeɪt/

objurgate

réprimander sévèrement
Meaning
to scold or rebuke severely
Example
The teacher objurgated the student for being dishonest.
Le professeur a réprimandé sévèrement l'élève pour son malhonnêteté.
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 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.
A1 adjective/adverb /ˈoʊnli/

only

seul
Meaning
without others; solely
Example
He is the only person who knows the secret.
Il est la seule personne qui connaît le secret.
B1 noun ˌɔː.ɡən.aɪˈzeɪ.ʃən

organization

organisation
Meaning
An organized group of people with a particular purpose, such as a business or government department.
Example
The organization was officially inaugurated in 2024.
L'organisation a été inaugurée officiellement en 2024.
C1 adjective /ˌaʊtˈspoʊkən/

Outspoken

franc
Meaning
frank; speaking directly
Example
She is known for being outspoken about social issues.
Elle est connue pour être franche sur les problèmes sociaux.
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 /ˈəʊpəs/

opus

œuvre créative
Meaning
A creative work, especially a large and important piece of music or art.
Example
The composer considered the symphony his greatest opus.
Le compositeur considérait la symphonie comme sa plus grande œuvre créative.
B1 adjective /ˌoʊvərˈsiːz/

overseas

à l'étranger
Meaning
in or to a foreign country across the sea
Example
He went overseas for higher education.
Il est allé à l'étranger pour ses études supérieures.
B1 noun /ˌɒpəˈreɪʃən/

operation

opération
Meaning
an act or process of functioning or operating
Example
The hospital performed a successful operation.
L'hôpital a effectué une opération réussie.
C1 adjective /ˌoʊvərˈbloʊn/

overblown

exagéré
Meaning
excessively exaggerated or inflated
Example
The controversy was overblown by the media.
La controverse a été exagérée par les médias.
A1 verb, adjective /oʊn/

own

posséder
Meaning
to possess something; belonging to oneself
Example
She owns a beautiful house in the city.
Elle possède une belle maison en ville.
C1 noun ˌɒb.səˈlɛs.əns

obsolescence

obsolescence
Meaning
The process of becoming obsolete or outdated and no longer used.
Example
The rapid advancement of technology leads to the obsolescence of old devices.
Le progrès rapide de la technologie entraîne l’obsolescence des anciens appareils.
C2 noun /ˈoʊɡər/

ogre

ogre
Meaning
A mythical monster, often depicted as large, hideous, and cruel; metaphorically, a cruel or terrifying person.
Example
The villagers feared the ogre who lived in the dark forest.
Les villageois craignaient l'ogre qui vivait dans la forêt sombre.
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.
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.
B1 noun /ˈɔːfɪsər/

officer

officier
Meaning
a person in a position of authority, especially in law enforcement
Example
The officer gave him a ticket for speeding.
L'officier lui a donné une amende pour excès de vitesse.
C2 noun /ˈɔːfəl/

offal

abats
Meaning
the internal organs and entrails of an animal used as food; waste parts
Example
The butcher prepared sausages using pork offal.
Le boucher a préparé des saucisses en utilisant des abats de porc.
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.
C1 noun /ˈoʊvərˌtoʊn/

overtone

connotation subtile
Meaning
A subtle quality, implication, or additional meaning beyond the obvious.
Example
His speech had political overtones that were hard to ignore.
Son discours avait des connotations politiques qu'il était difficile d'ignorer.
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.
C1 noun /oʊˈveɪʃən/

ovation

ovation
Meaning
an enthusiastic show of approval, especially by clapping hands
Example
The actor received a standing ovation after his performance.
L'acteur a reçu une ovation debout après sa performance.
C1 noun /ˈoʊ.mən/

Omen

un signe de bonne ou mauvaise chance future
Meaning
an event regarded as a sign of future good or bad luck
Example
Many people consider a black cat crossing your path a bad omen.
Beaucoup de gens considèrent qu'un chat noir traversant votre chemin est un mauvais présage.
C1 verb /əbˈsɛs/

obsess

obséder
Meaning
To preoccupy or fill the mind of someone continually and to an excessive degree.
Example
She tends to obsess over small details.
Elle a tendance à s'obséder sur de petits détails.
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.
C2 noun /ɒmˈnɪpətəns/

omnipotence

omnipotence
Meaning
The quality of having unlimited power or authority.
Example
Many religions describe God’s omnipotence as absolute.
De nombreuses religions décrivent l'omnipotence de Dieu comme absolue.
C1 verb /uːz/

ooze

suinter
Meaning
to slowly flow or leak out through small openings or pores
Example
Blood began to ooze from the small cut.
Le sang a commencé à suinter de la petite coupure.
B2 noun/verb /ˌoʊvərˈlæp/

overlap

chevauchement
Meaning
To extend over and cover partly; an area where things coincide.
Example
The two meetings overlap by an hour.
Les deux réunions se chevauchent d'une heure.
B2 verb /əˈblaɪdʒ/

oblige

obliger
Meaning
to compel or require someone to do something; to help or do a favor
Example
I would be happy to oblige you with the information you need.
Je serais heureux de vous obliger avec les informations dont vous avez besoin.
A1 adjective /oʊˈkeɪ/

ok

d'accord
Meaning
used to indicate agreement, approval, or understanding
Example
Okay, let's go to the park.
D'accord, allons au parc.
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.
B2 noun ˈəʊ.və.hed

overhead

frais généraux
Meaning
Ongoing business expenses not directly attributable to creating a product or service.
Example
The company reduced its overhead to increase profits.
L’entreprise a réduit ses frais généraux pour augmenter ses bénéfices.
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.
C2 noun /oʊˈbleɪʃən/

oblation

oblation
Meaning
a religious offering, especially of bread or wine to God
Example
The priest placed the oblation on the altar during the ceremony.
Le prêtre a placé l'oblation sur l'autel pendant la cérémonie.
C1 noun /oʊˈbɪt.ʃu.er.i/

Obituary

nécrologie
Meaning
a notice of someone's death published in a newspaper; biographical account of deceased person
Example
The newspaper published his obituary yesterday.
Le journal a publié son nécrologie hier.
B2 adverb /ˈaʊtraɪt/

Outright

directement; complètement; sans réserve
Meaning
completely; directly; without reservation or concealment
Example
She rejected the proposal outright.
Elle a rejeté la proposition directement.
C1 noun ˌɒk.sɪˈdeɪ.ʃən

oxidation

oxydation
Meaning
A chemical reaction that involves the combination of a substance with oxygen, often causing deterioration.
Example
Oxidation causes metal surfaces to weaken.
L'oxydation affaiblit les surfaces métalliques.
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.
B1 adverb /əˈrɪdʒɪnəli/

originally

à l'origine
Meaning
in the beginning, at first
Example
Originally, she wanted to be a doctor.
À l'origine, elle voulait être médecin.
B2 noun /ˈaʊtˌbreɪk/

outbreak

épidémie
Meaning
a sudden start or occurrence of something unpleasant, like disease or violence
Example
There was an outbreak of flu in the city.
Il y a eu une épidémie de grippe dans la ville.
B2 noun /ˈɔːɡənɪzəm/

organism

organisme
Meaning
a living thing that has an organized structure and can grow and reproduce
Example
Every organism needs water to survive.
Chaque organisme a besoin d'eau pour survivre.
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.
B2 noun /əˌrɪʒ.əˈnæl.ə.ti/

Originality

originalité
Meaning
the quality of being novel or unusual; the ability to think independently and creatively
Example
The artist's work showed great originality and creativity.
Le travail de l'artiste a montré une grande originalité et créativité.
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.
B2 noun /ˈaʊt.saɪ.dər/

Out-sider

étranger
Meaning
a person who does not belong to a particular group; someone not accepted by a group
Example
As an outsider, he found it difficult to understand their traditions.
En tant qu'outsider, il a trouvé difficile de comprendre leurs traditions.
C2 adjective /əbˈsiːkwɪəs/

obsequious

servile
Meaning
Excessively obedient or attentive in a servile way.
Example
The waiter gave an obsequious bow to every customer.
Le serveur fit une révérence servile à chaque client.