These words are from the IELTS 4000 Academic Word List and the sample sentences are taken from Cambridge free online dictionary.
affirm: (verb) assert; confirm
She affirmed her intention to apply for the post.
affirmation: (noun) positive assertion; confirmation; solemn pledge by one who refuses to take an oath
We welcome the government's affirmation of its intention to act.
affirmative: (adjective) confirmative; ratifying; giving assent or approval; confirming
He gave me an affirmative reply.
afford: pay; provide; have the financial means for; bear the cost of
I don't know how he can afford a new car on his salary.
affordable: (adjective ) not expensive / able to pay for
The newly opened store is selling their goods with very affordable prices.
agency: (noun) a business that serves other businesses; an administrative unit of government
He has an advertising agency.
agent: (noun) one that acts on behalf of other persons or organizations
Please contact our agent in the main branch for further information.
aggravate: (verb) worsen; make worse or more troublesome
Attempts to restrict parking in the city centre have further aggravated the problem of traffic congestion.
aggregate: (adjective ) gather into a mass, sum, or whole; amount to
The seven companies have an aggregate turnover of £5.2 million.
aggregation: (noun) several things grouped together or considered as a whole
A galaxy is an aggregation of stars.
aggressive: (adjective) making assaults; unjustly attacking; combative; hostile; tending to spread quickly
Men tend to be more aggressive than women.
aggressor: (noun) one that engages in aggression; person who first attacks
He sued his aggressor for physical injury
agitate: (verb) cause to move with violence or sudden force; upset; disturb
I didn't want to agitate her by telling her the truth.
agitation: (noun) anxiety; extreme emotional disturbance
He arrived home in a state of agitation.
agony: (noun) extreme pain of mind or body; anguish; last struggle of life; death struggle
We've both suffered agonies of guilt over what happened.
agreeable: (adjective) ready to consent or submit; acceptable
We need to find a compromise that is agreeable to both sides of the party.
agreement: (noun) state of agreeing; harmony of opinion, statement, action, or character
The dispute was settled by an agreement that satisfied both sides.
agriculture: (noun) practice of cultivating the land or raising stock
Agriculture is still largely based on traditional methods in some countries.
aid: (noun) person or thing that promotes or helps in something done; helper; assistant
Emergency aid was sent to the flood victims.
ailment: (noun) sickness; illness; affliction
You can treat minor ailments yourself.
aim: (noun) point or direct towards an object or spot with the intent of hitting it
The aim of the movie was to make people laugh.
air: (verb) to say your opinions / be broadcast on television or radio
The meeting will give us all a chance to air our views
aircraft: (noun) vehicle that can fly, such as an airplane, helicopter, balloon
He is an expert of flying an aircraft.
aisle: (noun) passageway between rows of seats, as in an auditorium or an airplane; wing of a building
The beautiful bride is walking down the aisle.
ajar: (adjective) half-open; slightly turned or opened
Don’t leave the door of my car ajar!
alert: (noun)warning serves; alarm; condition of heightened watchfulness or preparation for action
There was a bomb alert in the city yesterday.
alien: (noun) dissimilar, inconsistent, or opposed in nature; very different place, society, or person
There has been sighting of aliens in the past years.
alienate: (verb) cause to become unfriendly or hostile; transfer property or ownership; isolate or dissociate emotionally
Disagreements can alienate teenagers from their families.
alike: (adjective) similar; in the same manner or to the same degree
My dad and I look alike.
alliance: (noun) state of being allied; act of allying or uniting; a union or connection of interests between families, states, parties
NATO is sometimes called the Atlantic Alliance.
allocate: (verb) assign; distribute according to plan
The government is allocating £10 million for health education.
allot: (verb) parcel out in parts or portions; distribute to each individual concerned; assign as a share or lot
They allotted a separate desk to everyone.
ally: (noun) confederate; partner; collaborator
The United States is an ally of Saudi Arabia.
alone: (adjective) solitary; by oneself
I don’t like being alone.
alongside: (adverb) along or by the side; side by side with
A car pulled up alongside ours.