Synonyms: dirty, filthy, grubby, grimy, soiled, squalid
Antonym: clean

Synonyms:

dirty: not clean
Example: Playing rugby gets your clothes dirty. Someone has to wash all the dirty plates.

filthy: very dirty
Example: His hands were filthy from changing the car tyre.

grubby: so dirty as to be unpleasant
Example: Grubby children were playing in the street.
He was wearing a grubby old shirt.

grimy: covered with old dirt that is difficult to remove
Example: The furniture was broken and the windows were grimy.

soiled: spoiled by dirt or other unpleasant substances
Example: The sheets on the bed were soiled.

squalid: referring to a room or building that is dirty and unpleasant
Example: The prisoners are kept in squalid conditions.

Antonym:
clean: not dirty

Synonyms: defeat, beat, conquer, overcome, triumph, thrash

defeat: to succeed against someone in a game, fight or vote
Example: Our team has not been defeated so far this season. The soldiers defeated
the enemy’s attempt to take the town.

Example: The ruling party was heavily defeated in the presidential election. The proposal was defeated by 10 votes to 3.

beat: to win a game against another player or team
Example: They beat their rivals into second place. Our football team beat France
2 – 0. They beat us by 10 goals to 2. My children can usually beat me at tennis.

conquer: to defeat people by force
Example: The army had conquered most of the country.

overcome: to gain victory over an enemy
Example: The boys quickly overcame their attackers.

triumph: to achieve a great success
Example: The team triumphed over their long-term rivals.

thrash: (informal) to defeat another person or team easily
Example: She expects to be thrashed by the champion.

Synonyms: dead, late, extinct
Antonyms: alive, live
Synonyms:

dead: not living any more
Example: His parents are both dead. Dead fish were floating in the water.

late: a more polite word than ‘dead’, used about people
Example: His late father was a director of the company.

extinct: no longer in existence, because all of the same kind have died
Example: These birds are in danger of becoming extinct.

Antonyms:
alive: living (not used in front of a noun: ‘the fish is alive’ but ‘a live fish’)

live: living, not dead

Synonyms: cut, slice, chop, slash

cut: to divide, reduce or remove something using a sharp tool, e.g. a knife or scissors

Example: The meat is very tough – I can’t cut it with my knife. He needs to get his hair cut.

Example: There were six children, so she cut the cake into six pieces.

slice: to cut something into thin pieces
Example: She stood at the table slicing bread and meat for lunch.

chop: to cut something roughly into small pieces with a knife or other sharp tool
Example: He spent the afternoon chopping wood for the fire.

slash: to make a long cut in something with a knife, often violently
Example: He slashed the painting with a kitchen knife.

Synonyms: courage, bravery, nerve, guts
Antonym: cowardice

Synonyms:
courage: the ability to deal with a dangerous or unpleasant situation
Example: She showed great courage in attacking the burglar. I didn’t have the
courage to disagree with him.

bravery: the ability to do dangerous or unpleasant things without being afraid
Example:  We admired her bravery in coping with the illness. He won an award for bravery.

nerve: the ability to keep your fear under control in order to achieve something
Example: It takes a lot of nerve to disagree with your friends.
He went over to speak to her but at the last minute he lost his nerve.

guts: (informal) courage
Example: She had the guts to tell the boss he was wrong.

Antonym:
cowardice: the state of being afraid and not brave

Synonyms: correct, accurate, exact, true
Antonym: incorrect

Synonyms:

correct: without any mistakes
Example: Some of your answers were not correct.

accurate: correct in all details
Example: Are the figures accurate? We asked them to make an accurate copy of the plan.

exact: completely correct in every detail
Example: Can you tell me the exact words she used?
We need to know the exact route she took that night.

true: correct according to facts or reality
Example: What he says is simply not true.
Is it true that he’s been married twice?

Antonym:
incorrect: wrong, not correct

Synonyms: copy, reproduce, duplicate, clone, replicate

copy: to make something which looks like something else
Example: He stole a credit card and copied the signature

reproduce: to make a copy of something such as artistic material or musical sounds
Example: Some of the paintings have been reproduced in this book. It is very difficult to reproduce the sound of an owl accurately.

duplicate: to make a copy of a document such as a letter
Example: She duplicated the letter and put the copy into a file.

clone: to create an exact genetic copy of an individual animal or plant
Biologists have successfully cloned a sheep.

replicate: (formal) to do or make something in exactly the same way as before
Example: Can the experiment be replicated?

Synonyms: contestant, candidate, candidate, contender, applicant, entrant

contestant: a person who takes part in a competition
Example: The two contestants shook hands before the match.

candidate: a person who applies for a job
Example: We interviewed six candidates for the post of assistant manager.

candidate: a person who has entered for an examination
Example: Candidates are given three hours to complete the exam.

contender: a person who takes part in a competition, especially someone who is likely
to win
Example: He’s a definite contender for the world title.

applicant: a person who applies for something job applicants
Example: Applicants for licences must fill in this form.

entrant: a person who takes part in a race, examination or competition
Example: There are over a thousand entrants for the race.

Synonyms: complain, object, protest, grumble, whine
Antonym: praise

Synonyms:
complain: to say that something is not good or does not work properly
Example: The shop is so cold the staff have started complaining. They are complaining that our prices are too high.

object: to say that you do not like something or you do not want something to
happen
Example: We object to being treated like children.
He objected that the pay was too
low.

protest: to say that you strongly disapprove of something, sometimes by shouting
or speaking angrily
Example: Passengers began protesting about the lack of heating on the train. My
assistant protested about having to work at the weekend.

grumble: to complain in a bad-tempered way, especially regularly and often about
unimportant things
Example: He’s always grumbling about the music from the flat above.

whine: to complain frequently in a way that annoys other people
Example: She’s always whining about how little money she has.

Antonym:
praise: to express strong approval of something or someone

Synonyms: competition, contest, match, game

competition: an event in which several teams or people compete with each other
Example: He won first prize in the photography competition.

contest: any event or situation in which people compete with each other
a beauty contest. 
Example: There are three senior politicians in this leadership
contest.

match: a single occasion when two teams or players compete with each other in a
sport
Example: We watched the football match on TV.
He won the last two tennis
matches he played.

game: an activity in which people compete with each other using skill, strength
or luck
Example: She’s not very good at games like chess.
I enjoy a game of cards.