CEFR Level
a fertile spot in a desert where water is found; a pleasant relief
"After hours in the desert, they finally reached an oasis."
a solemn promise, often invoking a divine witness
"She took an oath to tell the truth in court."
Extremely overweight; having an excessive amount of body fat.
"The doctor advised the obese patient to adopt a healthier lifestyle."
A notice of a person's death, often published in a newspaper with a brief biography.
"The newspaper published an obituary for the famous writer."
arousing distaste or opposition; unpleasant or offensive
"His objectionable behavior made everyone uncomfortable."
a person who expresses opposition or disapproval to something
"The objector raised his concerns during the town meeting."
Required by law, rule, or custom; mandatory.
"Wearing a helmet is obligatory when riding a motorcycle."
Willing to help or do favors; accommodating.
"The staff at the hotel were very obliging and friendly."
Not explicit or direct in addressing a point; slanting or indirect.
"She made an oblique reference to his past mistakes."
To completely destroy, remove, or wipe out.
"The town was obliterated by the powerful earthquake."
The state of being completely forgotten or unknown; the state of being unconscious or unaware.
"The ancient city fell into oblivion after the empire collapsed."
Extremely unpleasant, offensive, or annoying.
"The obnoxious behavior of the guest ruined the party."
The practice of following a custom, rule, or religious law.
"The festival is held in observance of a centuries-old tradition."
Quick to notice details or attentive to rules and customs.
"She is very observant and rarely misses any detail."
A building equipped for observing astronomical or meteorological events.
"The observatory is open to the public on weekends."
Relating to or characterized by an obsession; thinking about something too much.
"He has an obsessive interest in cleanliness."
The state of being no longer useful or in fashion; becoming outdated.
"The rapid obsolescence of smartphones makes people upgrade frequently."
No longer in use or out of date.
"Floppy disks are now completely obsolete."
A doctor specializing in pregnancy, childbirth, and women's reproductive health.
"The obstetrician monitored the mother’s health throughout the pregnancy."
Refusing to change one’s opinion or behavior despite persuasion.
"The child was obstinate about not eating vegetables."
To block or prevent movement, progress, or action.
"A fallen tree obstructed the road."
Something that blocks or gets in the way; the action of obstructing.
"There was an obstruction on the railway track."
deliberately creating difficulties or preventing progress; hindering or blocking something
"The obstructive policies hindered economic growth."
slow to understand; annoyingly insensitive; also refers to an angle greater than 90° and less than 180°
"He was too obtuse to realize the insult."
Relating to mysterious, supernatural, or magical powers and practices.
"She had always been fascinated by the occult and its hidden knowledge."
An incident, event, or something that happens.
"The occurrence of such storms is rare in this region."
The ongoing decrease in the pH of the Earth's oceans, caused by the absorption of carbon dioxide from the atmosphere.
"Ocean acidification is caused by atmospheric CO2 absorption."
A polygon with eight sides and eight angles.
"The stop sign is shaped like an octagon."
Something strange or unusual.
"The bright pink building was an oddity in the small town."
a long, adventurous journey; a series of experiences
"Her career has been an odyssey of challenges and achievements."
a person who commits a crime or does something wrong
"The police caught the offender quickly."
Without previous thought or preparation; casual and sometimes dismissive.
"She gave an offhand reply to his serious question."
To perform official duties, especially in a ceremony or as a referee.
"The priest will officiate the wedding ceremony."
To counterbalance or compensate for something.
"The company's losses were offset by gains in other departments."
A branch or result that develops from something larger or more important.
"The startup was an offshoot of a major tech company."
a person's child or children; an animal's young
"The bird carefully fed its offspring."
A smooth, oily substance applied to the skin for healing or soothing.
"The doctor prescribed an ointment for the burn on his arm."
A small group of people having control of a country, organization, or institution.
"The nation was ruled by a wealthy oligarchy that controlled all resources."
an event regarded as a sign of future good or bad luck
"Many people consider a black cat crossing your path a bad omen."
Giving the impression that something bad or unpleasant is going to happen.
"Dark clouds gave an ominous sign of an approaching storm."
The act of leaving out or excluding something; something that has been left out.
"Her omission of important details caused confusion."
present everywhere at the same time
"In the digital age, social media feels omnipresent in our lives."
eating both plants and animals
"Humans are generally considered omnivorous creatures."
involving a great deal of effort, difficulty, or burden
"Fulfilling the contract proved to be an onerous task for the company."
The beginning of something, especially something unpleasant.
"The onset of winter brought cold winds and snow."
A fierce or destructive attack.
"The village faced an onslaught of enemy forces."
