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All Vocabulary Cards All Vocabularies
B1 verb /əˈkɜːr/

occur

Meaning
to happen or take place; to be found or present
Example
The accident occurred at the intersection during rush hour.
B1 noun /ˈɑb.stə.kəl/

Obstacle

Meaning
something that blocks or makes progress difficult; a barrier
Example
Bad weather was the main obstacle to our journey.
B2 verb /ˌoʊvərˈkʌm/

overcome

Meaning
To succeed in dealing with a problem or difficulty.
Example
You can overcome procrastination with planning.
A2 adjective /ˈɑp.ə.zɪt/

Opposite

Meaning
Contrary; completely different; facing each other; reverse;
Example
They have opposite views on politics but remain good friends.
C1 noun /ˈɒfʃuːt/

offshoot

Meaning
A branch or result that develops from something larger or more important.
Example
The startup was an offshoot of a major tech company.
C2 adjective /ˌoʊdəˈrɪfərəs/

odoriferous

Meaning
having or giving off a smell, especially a strong or pleasant one
Example
The garden was filled with odoriferous flowers.
B2 verb /əˈblaɪdʒ/

oblige

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.
C1 adverb /ˈaʊtwədli/

Outwardly

Meaning
on the surface; externally; in appearance
Example
Outwardly, he seemed calm, but inside he was nervous.
B2 adjective /ˈɒp.tɪ.məl/

optimal

Meaning
Best or most favorable; the most effective under particular conditions.
Example
The optimal temperature for plant growth is around 25°C.
C1 adjective /ˌɒmnɪˈprezənt/

omnipresent

Meaning
(of God) present everywhere at the same time.
Example
Social media has become an omnipresent force in modern society.
C1 adjective /ɒmˈnɪv.ər.əs/

Omnivorous

Meaning
eating both plants and animals; feeding on various kinds of food
Example
Bears are omnivorous animals that eat both plants and meat.
C2 noun ˈɒpjʊləns

opulence

Meaning
Great wealth or luxuriousness.
Example
The opulence of the mansion was evident in its ornate furnishings.
C1 verb /ˌoʊvərˈpaʊər/

overpower

Meaning
To defeat or gain control over someone or something by using greater strength or force.
Example
The soldiers managed to overpower the enemy forces.
B1 verb /əbˈzɜːrv/

observe

Meaning
to watch carefully; to notice or perceive something
Example
Scientists observe the behavior of animals in the wild.
A1 adjective /oʊld/

old

Meaning
having lived for a long time; not new or young
Example
He still drives his old car.
B2 verb /ˌoʊvərˈteɪk/

overtake

Meaning
to catch up with and pass someone or something; to surpass
Example
The runner managed to overtake his competitor in the final lap.
B2 noun ˈəʊnəʃɪp

ownership

Meaning
The act, state, or right of possessing something; legal title to something.
Example
Ownership of resources was crucial.
C1 adjective /ˈɒm.ɪ.nəs/

Ominous

Meaning
giving the impression that something bad will happen; threatening; foreboding
Example
The dark clouds looked ominous before the storm.
C1 noun /ˈoʊ.vər spɪl/

Over-spill

Meaning
the overflow of liquid from a container; excess that cannot be contained
Example
The overspill from the river flooded nearby farms.
B2 noun /ˌaʊtˈsaɪdə(r)/

outsider

Meaning
a person who is not accepted as a member of a particular group or community
Example
As a new student, she often felt like an outsider at school.
C1 adjective /ˌɒbsəˈliːt/

obsolete

Meaning
No longer in use or out of date.
Example
Floppy disks are now completely obsolete.
B1 noun /əˈkeɪ.ʒən/

Occasion

Meaning
a particular time or instance of an event; a special celebration
Example
Their wedding was a joyous occasion.
C2 verb /ˈɑːbdʒərˌɡeɪt/

objurgate

Meaning
to scold or rebuke severely
Example
The teacher objurgated the student for being dishonest.
C2 adjective /ˈɔːrəˌtʌnd/

orotund

Meaning
full, rich, and clear in sound; pompous in style
Example
The actor's orotund voice filled the theater.
C2 noun /ˈɑb.lə.kwi/

Obloquy

Meaning
harsh criticism or verbal abuse; strong public condemnation
Example
The politician faced obloquy after the scandal.
C1 adjective /ˌɔː.riˈen.təl/

Oriental

Meaning
relating to the countries of East Asia; eastern
Example
The museum has a beautiful collection of oriental art.
C1 adjective /ˌəʊ.vərˈɑː.tʃɪŋ/

overarching

Meaning
Comprehensive or all-embracing; forming an arch over something.
Example
The overarching theme of the book is human resilience.
A1 pronoun /aʊər/

our

Meaning
belonging to or associated with the speaker and one or more other people
Example
This is our house.
C1 verb /ˌoʊvərˈʃædoʊ/

overshadow

Meaning
to appear more important or significant than something else, reducing its impact
Example
The scandal overshadowed his achievements.
C1 noun ˈoʊʃən əˌsɪdɪfɪˈkeɪʃən

ocean acidification

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.
C1 adjective /ˌɔːrθəˈpiːdɪk/

orthopedic

Meaning
Relating to the correction of deformities of bones or muscles.
Example
She visited an orthopedic surgeon for her back pain.
B1 verb /ˈɔːrɡənaɪz/

organize

Meaning
to arrange systematically; to plan and coordinate
Example
She organized a surprise party for her friend.
B2 noun /ˈɒpəreɪtər/

operator

Meaning
a person who operates equipment, a business, or controls something
Example
The machine operator ensured that everything ran smoothly.
C1 noun /ˈɒktəɡən/

octagon

Meaning
A polygon with eight sides and eight angles.
Example
The stop sign is shaped like an octagon.
A1 adverb /ɔːf/

off

Meaning
away from a place, position, or time; not functioning
Example
He turned off the light before leaving the room.
C2 noun /ˈoʊ.kəm/

oakum

Meaning
loose fibers obtained by untwisting old ropes, used for caulking ships
Example
The shipbuilders used oakum to seal the gaps in the wooden planks.
C1 adjective /ˈəʊnərəs/

onerous

Meaning
involving a great deal of effort, difficulty, or burden
Example
Fulfilling the contract proved to be an onerous task for the company.
B2 verb /əˈrɪdʒɪneɪt/

originate

Meaning
to come into existence; to begin; to create or produce
Example
The tradition originated in ancient times.
B2 adjective /ˈɔː.rəl/

Oral

Meaning
spoken rather than written; relating to the mouth
Example
The oral examination will test your speaking skills.
C2 noun /ˌɒstɛnˈteɪʃən/

ostentation

Meaning
excessive display of wealth or knowledge intended to attract admiration or envy
Example
The billionaire’s party was full of ostentation and luxury.
A1 interjection /oʊ/

oh

Meaning
used to express surprise, realization, or understanding
Example
Oh, I didn't know you were here!
C1 adjective /ˌaʊt əv ðə ˈweɪ/

out-of-the-way

Meaning
remote or unusual; not in a convenient or usual location
Example
They stayed in an out-of-the-way village.
C2 noun /ˈɔːrdnəns/

ordnance

Meaning
Military supplies including weapons, ammunition, and combat equipment.
Example
The army stored ordnance in a secure facility outside the city.
C2 noun /ˈɔːrɪndʒfɪn ˈleɪbiːoʊ/

Orangefin labeo

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.
C2 adjective /ɑːlˈfæktəri/

olfactory

Meaning
Relating to the sense of smell.
Example
The perfume activated her olfactory nerves immediately.
C2 noun /ˈoʊdiəm/

odium

Meaning
general or widespread hatred or disgust directed toward someone as a result of their actions
Example
The scandal brought public odium on the corrupt minister.
B2 adjective /ˈɔː.də.li/

Orderly

Meaning
well-organized; systematic; peaceful
Example
Please keep your desk orderly and clean.
C1 noun /ˈɔːrθədɑːksi/

orthodoxy

Meaning
traditional or generally accepted beliefs and practices
Example
The religious leader defended the orthodoxy of the faith.
C1 verb /aʊst/

oust

Meaning
To remove someone from a position or place of power or authority.
Example
The rebels ousted the dictator from power.
A1 noun /ɒkˈtoʊbər/

october

Meaning
the tenth month of the year in the Gregorian calendar
Example
The weather becomes cooler in October.
C2 noun /əbˈstɛtrɪks/

obstetrics

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.
C2 verb ˈɑːb.fə.skeɪt

obfuscate

Meaning
Render obscure, unclear, or unintelligible.
Example
Politicians often obfuscate facts to mislead people.
A1 verb, adjective /oʊn/

own

Meaning
to possess something; belonging to oneself
Example
She owns a beautiful house in the city.
C2 adjective /əbˈsiːkwɪəs/

obsequious

Meaning
Excessively obedient or attentive in a servile way.
Example
The waiter gave an obsequious bow to every customer.
C1 adjective /ˈɒptɪkəl/

optical

Meaning
related to or used in seeing or sight
Example
The optical illusion fooled everyone at the exhibition.
C1 verb /ˌaʊtˈweɪ/

outweigh

Meaning
To be more important, valuable, or significant than something else.
Example
The benefits of the new policy outweigh the risks.
C1 noun /əbˈstrʌkʃən/

obstruction

Meaning
Something that blocks or gets in the way; the action of obstructing.
Example
There was an obstruction on the railway track.
B2 noun/verb /ˈoʊvərˌdoʊs/

overdose

Meaning
An excessive and dangerous amount of a drug; to take too much of a substance.
Example
He was rushed to the hospital after a drug overdose.
C2 noun /ˌɒpəˈrɛtə/

operetta

Meaning
a short opera with light and humorous themes
Example
The theater staged a famous operetta by Gilbert and Sullivan.
C2 noun /ɒmˈnɪʃəns/

omniscience

Meaning
the state of knowing everything
Example
The novel's narrator has an air of omniscience, revealing every character's thoughts.
B2 noun /ˈaʊtˌbreɪk/

outbreak

Meaning
a sudden start or occurrence of something unpleasant, like disease or violence
Example
There was an outbreak of flu in the city.
B1 noun ˌɒpəˈtjuːnɪtiz

opportunities

Meaning
A set of circumstances that makes it possible to do something; chances for advancement or success.
Example
Opportunities for jobs decreased.
B2 adverb /ˌoʊvərˈnaɪt/

Overnight

Meaning
during the night; suddenly; very quickly
Example
The city was transformed overnight.
C1 noun /ˈɔːrdɪnəns/

ordinance

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.
C2 adjective /ˈɑːsɪˌfaɪd/

ossified

Meaning
Turned into bone or become rigid; unwilling to change.
Example
The company had an ossified management structure that resisted innovation.
A1 preposition /ʌv/

of

Meaning
expressing the relationship between a part and a whole
Example
The book is on the table, in front of the window.
B2 noun /ˈɒp.tɪ.mɪ.zəm/

optimism

Meaning
Hopefulness and confidence about the future or the successful outcome of something.
Example
Her optimism helped her overcome difficult times.
C1 verb /ˌoʊvərˈrʌn/

overrun

Meaning
to spread over or occupy completely; to exceed a limit or time
Example
The garden was overrun with weeds.
C2 noun /ˌɔːrəˈtɔːri.oʊ/

oratorio

Meaning
A large-scale musical composition for orchestra, choir, and soloists, usually on a sacred theme, performed without costumes or scenery.
Example
Handel's 'Messiah' is one of the most famous oratorios ever written.
C2 noun /ˈɒbsɪkwi/

obsequy

Meaning
A funeral rite, usually used in plural form obsequies.
Example
The village gathered for the obsequy of their beloved teacher.
A2 adjective /ˈɔː.dɪ.nər.i/

Ordinary

Meaning
normal; usual; not special
Example
It was just an ordinary day at the office.
B2 adjective /ˈaʊtˌɡoʊɪŋ/

outgoing

Meaning
Friendly and sociable; inclined to mix with others.
Example
He is an outgoing person who loves meeting new people.
C1 adjective /ˌɒstɛnˈteɪʃəs/

ostentatious

Meaning
Characterized by a showy or pretentious display intended to impress others.
Example
He wore an ostentatious gold chain to the party.
B2 verb /əbˈteɪn/

obtain

Meaning
to get or acquire something
Example
You need to obtain a visa before traveling abroad.
C2 noun /ˌɔːrnɪˈθɑːlədʒi/

ornithology

Meaning
the scientific study of birds
Example
She pursued ornithology to understand the migration patterns of birds.
B2 noun /əbˈsɛʃən/

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.
C2 noun /ˈɒlɪv bɑːb/

Olive barb

Meaning
A small freshwater fish with olive-colored body and barbels
Example
The olive barb is commonly found in South Asian rivers.
C1 noun /ˈɑn.set/

Onset

Meaning
the beginning or early stages of something; the start of a medical condition
Example
The onset of winter brought heavy snowfall.
B2 verb /ˌoʊvərˈpeɪ/

overpay

Meaning
To pay more than is necessary or reasonable.
Example
She realized she had overpaid for the concert tickets.
C1 verb /aʊtˈlɪv/

outlive

Meaning
to live longer than someone or something else
Example
She outlived all her siblings.
B1 adjective /əˈbiː.di.ənt/

Obedient

Meaning
willing to comply with orders or instructions; submissive
Example
The obedient student always follows the teacher's instructions.
C1 noun /əˈpreʃ.ən/

Oppression

Meaning
cruel or unjust treatment or exercise of authority; the state of being subject to harsh treatment
Example
The people fought against political oppression.
C1 noun /ˈɒf.sprɪŋ/

offspring

Meaning
a person's child or children; an animal's young
Example
The bird carefully fed its offspring.
A2 adjective /əˈlɪmpɪk/

olympic

Meaning
related to the Olympic Games, a major international sporting event
Example
She trained hard to compete in the Olympic Games.
C2 noun /ˈɑːbəlɪsk/

obelisk

Meaning
A tall, four-sided, narrow tapering monument with a pyramid-shaped top.
Example
The ancient Egyptians built obelisks to honor their gods.
C1 noun ɔːrˈdiːl

ordeal

Meaning
A physical or mental painful experience that must be endured
Example
Surviving the wilderness was a tough ordeal for them.
B1 noun /ˌɑk.jəˈpeɪ.ʃən/

Occupation

Meaning
a job or profession; the action of taking control of a place
Example
Teaching is her chosen occupation.
A1 preposition, adverb /ˈoʊvər/

over

Meaning
across, on top of, or beyond
Example
The book is lying over the table.
C1 noun /ˈɑːdəsi/

odyssey

Meaning
a long, adventurous journey; a series of experiences
Example
Her career has been an odyssey of challenges and achievements.
A2 noun /ɔɪl/

Oil

Meaning
a viscous liquid derived from petroleum or plants, used for cooking or fuel
Example
Heat the oil in a pan before adding the vegetables.
B2 verb /ˌoʊvərˈloʊd/

overload

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.
B1 adjective /ˈɔːɡənaɪzd/

organized

Meaning
Arranged in a systematic way, especially on a large scale.
Example
An organized approach to work increases productivity and reduces stress.
C2 adjective /ˈoʊ.pən ˈhæn.dɪd/

Open-handed

Meaning
Generous; liberal; giving freely;
Example
He is very open-handed with his money and always helps those in need.
A2 noun /ˈʌv.ən/

Oven

Meaning
an enclosed compartment used for heating, baking, or drying food
Example
She baked cookies in the oven for thirty minutes.
C1 noun /əbˈdʒɛktər/

objector

Meaning
a person who expresses opposition or disapproval to something
Example
The objector raised his concerns during the town meeting.
A2 adjective /ˈaʊtdɔːr/

outdoor

Meaning
situated, existing, or done outside a building
Example
We planned an outdoor picnic for the weekend.
B1 verb /ˈɒpəreɪtɪŋ/

operating

Meaning
to control or manage the functioning of something
Example
The company has been operating in this market for five years.
B2 noun /əbˈzɜːvər/

observer

Meaning
a person who watches or notices something
Example
The observer took notes during the meeting.
C1 verb /ˈoʊvərˌhɔːl/

overhaul

Meaning
to examine thoroughly and repair or improve something that is worn or ineffective
Example
The company decided to overhaul its outdated computer system.
B2 noun ˈəʊ.və.hed

overhead

Meaning
Ongoing business expenses not directly attributable to creating a product or service.
Example
The company reduced its overhead to increase profits.
C2 verb /ˈoʊɡəl/

ogle

Meaning
To look at someone with obvious sexual interest.
Example
He kept ogling the models on the runway.
C2 noun /ˌɑːpərˈtuːnɪzəm/

opportunism

Meaning
The practice of taking advantage of opportunities regardless of principles or ethics.
Example
His decision was driven by opportunism, not values.
C2 noun /ˈoʊ.vər.let/

Overlet

Meaning
a thin mattress or pad placed over a bed for additional comfort
Example
The overlet makes the bed more comfortable to sleep on.
C1 noun /ˌɑːk.sɪˈmɔːr.ɒn/

oxymoron

Meaning
a figure of speech where two contradictory terms are combined
Example
The phrase 'deafening silence' is a classic oxymoron.
B1 noun /əˈpɪn.jən/

Opinion

Meaning
a view or judgment formed about something; a belief or assessment based on grounds short of proof
Example
In my opinion, this is the best solution.
B1 adjective /əˈkeɪ.ʒən.əl/

Occasional

Meaning
occurring infrequently or irregularly; happening from time to time
Example
She enjoys occasional walks in the park.
C2 adjective /ˈɒsiəs/

osseous

Meaning
consisting of or turned into bone; bony
Example
The fossil showed osseous structures of the ancient creature.
B2 adjective + noun ˈɒptɪməl ˈtempərətʃər

optimal temperature

Meaning
The best or most favorable temperature for a particular purpose
Example
Winter provides optimal temperature for farming.
C2 noun /ˌɒn.əˌmæt.əˈpiː.ə/

onomatopoeia

Meaning
The formation of a word from a sound associated with what is named.
Example
The word 'buzz' is an example of onomatopoeia.
C2 noun ˌɒbfəsˈkeɪʃən

obfuscation

Meaning
The action of making something obscure, unclear, or unintelligible.
Example
The obfuscation of the data made it difficult to interpret.
C1 verb /uːz/

ooze

Meaning
to slowly flow or leak out through small openings or pores
Example
Blood began to ooze from the small cut.
C2 verb /ˈɑːblɪˌɡeɪt/

obligate

Meaning
to bind legally or morally; to compel someone to do something
Example
The contract obligates the company to provide timely service.
C1 noun /ɒpˈtɒmətri/

optometry

Meaning
The practice or profession of examining the eyes and prescribing corrective lenses.
Example
She studied optometry at the university to become an eye specialist.
B2 verb /ˌoʊvərˈtɜrn/

overturn

Meaning
to turn something upside down or to reverse a decision or judgment
Example
The court decided to overturn the previous ruling.
C2 noun /oʊf/

Oaf

Meaning
a clumsy, stupid, or insensitive person
Example
Don't be such an oaf - handle the dishes carefully!
B2 noun /ˈaʊtˌfɪt/

outfit

Meaning
A set of clothes worn together, often for a particular occasion.
Example
She wore a beautiful outfit to the party.
A2 noun /ˈoʊpənɪŋ/

opening

Meaning
an act or instance of beginning something
Example
The opening of the new store was a huge success.
B1 adjective, adverb /ˈoʊvərɔːl/

overall

Meaning
in general or as a whole
Example
Overall, the project has been successful.
C1 verb /ˈɒp.tɪ.maɪz/

optimize

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.
C1 noun/verb /ˈoʊvərˌhæŋ/

overhang

Meaning
To extend outward and hang over something; a projecting part.
Example
The roof overhang provides shade in the summer.
C2 noun ˈoʊʃən ˌstrætɪfɪˈkeɪʃən

ocean stratification

Meaning
The formation of layers in ocean water due to differences in density.
Example
Ocean stratification affects marine biodiversity.