English English
CEFR LEVEL
3335 entries have no recorded CEFR level and are included in All.
o'clock
word A1used after a number to specify an exact hour of time
↗oak
word A2a large tree that bears acorns and produces hard, durable timber a large tree that produces acorns and has strong, hard wood
↗Oar
word C1a long pole with a flat blade used to propel and steer a boat through water by manual rowing
↗oasis
word B2a fertile or green spot in a desert, where water is found; a pleasant place of refuge or relief; a fertile spot in a desert where water is found; a pleasant refuge a fertile area in a desert where water is found; a peaceful or pleasant place a fertile spot in a desert where water is found; a pleasant relief
↗oath
word B2a solemn promise or formal declaration, often invoking a deity or moral code
↗obey
word B2to comply with an order, request, or law submitted by an authority
↗obfuscate
word C2To deliberately make something obscure, unclear, or difficult to understand.
↗obfuscation
word C2The action of making something obscure, unclear, or unintelligible.
↗object
word B1a thing that you can see or touch; in grammar, the receiver of an action a thing that can be seen and touched; a thing that can be seen and touched
↗objection
word B1An expression or feeling of disapproval or opposition; a reason for disagreeing.
↗objective
word B1something that you plan to achieve; a goal or aim
↗obligation
word B2an act or course of action to which a person is morally or legally bound; a duty or commitment
↗obliterate
word C1to destroy completely; to remove all traces of something; To destroy utterly; wipe out completely, to erase or remove something completely.; Destroy utterly; wipe out completely.
↗Oblivion
word C1the state of being completely forgotten; unconsciousness; complete forgetfulness
↗oblivious
word C1Not aware of or concerned about what is happening around oneself.
↗observation
word B1the act of watching carefully and noticing details; also a comment based on this the action of watching something carefully; a comment or remark the action or process of observing something carefully in order to gain information; The action of watching something carefully to gain information; a remark or comment.
↗observations
word B2Remarks, data, or notes based on watching, monitoring, or measuring something carefully.
↗observe
word B1to watch carefully and attentively; to notice or perceive something; to watch carefully; to notice or perceive something to watch carefully and attentively
↗observe closely
phraseto watch, inspect, or monitor something with intense concentration, attentiveness, and precision
↗observed
word B2Celebrated, marked, or followed a festival, holiday, or customary practice.
↗observer
word B2a person who watches or notices something, especially professionally a person who watches or notices something
↗obsolescence
word C2the process of becoming outdated and no longer used
↗obstacle
word B1A thing that blocks one's way or prevents or hinders progress; barrier or hurdle.; something that blocks or makes progress difficult; a barrier something that blocks your way or prevents progress
↗obstacles
word B1Things that block one's way or hinder progress.
↗Obstinacy
word C2stubborn refusal to change one's opinion or chosen course of action
↗obstinate
word C1Stubbornly refusing to change one's opinion or chosen course of action, despite attempts to persuade one to do so.
↗obtain
word B1to get or acquire something, especially by effort, request, or purchase
↗obviate
word C2to remove a need or difficulty; to prevent or make unnecessary
↗obvious
word B1easy to see, notice, or understand easily perceived or understood; clear and apparent to the mind easily perceived or understood; clear and apparent
↗obviously
word B1in a way that is clear and easy to see or understand in a way that is easily perceived or understood; clearly
↗occasion
word B1a particular event, time, or celebration
↗occasional
word B1occurring, appearing, or done infrequently and irregularly occurring infrequently or irregularly; happening from time to time happening or done sometimes but not regularly or often
↗occasionally
word B1at infrequent intervals; now and then or from time to time
↗occult
word C1Relating to mysterious, supernatural, or magical powers and practices.
↗occupation
word A2a person's job or regular work a job or profession; the action of taking control of a place a job or profession; the action or state of occupying a place; A job or profession; employment.
↗occupy
word B1to fill, enter, or take up a space, time, or position
↗occur
word B1to happen or take place, especially unexpectedly or as part of a process
↗ocean
word B1a very large expanse of sea, especially one of the main areas into which the sea is divided geographically; A very large expanse of sea, especially the main areas of sea between continents. a very large expanse of sea; a large quantity of something a very large expanse of sea; one of the main areas of sea a large body of salt water that covers most of the Earth's surface
↗ocean acidification
word C1The continuous reduction in pH levels of Earth's oceans caused by the uptake of anthropogenic carbon dioxide from the atmosphere.
↗ocean stratification
word C2The natural division of ocean water into distinct horizontal layers based on density, temperature, or salinity differences.
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