Antonyms

What are antonyms?
Antonyms are word with their opposites:

Man - woman
girl - boy
big - small
old - young
black - white
long - short
rich - poor
temporal - permanent
quiet - noisy
failure - success
ugly - beautiful
student - teacher
alive - dead
absence - presence

By adding a prefix

advantage - disadvantage
happy - unhappy
legal - illegal
kind - unkind
moral - immoral
obey - disobey
relevant - irrelevant
possible - impossible
safe - unsafe
lock - unlock
necessary - unnecessary
patient - impatient
visible - invisible
tidy - untidy
save - unsafe
normal - abnormal
just - unjust

By changing the prefix.

export - import
external - internal
ascend - descent
encourage - discourage
inside outside
increase - decrease

By changing the suffix

careless - careful
useless - useful
joyless - joyful
merciless - merciful
cheerless - cheerful
pitiless - pitiful

Synonyms

These are word which have similarity in meaning

abandon - leave
affectionate - loving
custom - habit
conversation - talk
astonish - surprise
ancient - old
help - aid
abundant - plentiful
quantity - amount
rank - position
rapid - quick
powerful - strong
profit - gain glance - book
join - unite
mad - insane
halt - stop
gap - hole
odor - smell
withdraw - retire
yearly - annually
disaster - calamity
difficult - hard
caution - care
vacant - empty
insolent - rude

Homonyms

There are words which sound the same perhaps have the same spelling but mean different things.

meat - meet
air - heir
die - dye
council - counsel
loan - lone
allowed - aloud
ate - eight
ant - and
flour - flower
hear - here
son - sun
heard - herd
hole - whole
holy - wholly
knows - nose
maid - made
week - would
see - sea
belle - bell
blew - blue
board - bored
buy - bye, by
ceiling - sealing
deer - dear
right - write
peace - piece
wait - weight
tail - tale
higher - hire
him - hymn
male - mail
steel - steal
prays - praise