Antonyms are words of the same grammatical class that have opposite meanings.
A list of antonyms is given below:  
abbreviation expansion
abandon retain
abate aggravate
abdicate claim
ability inability, disability
able unable
abolish retain
abnormal normal
above below
abstract concrete
absurd reasonable
abundance scarcity
accept reject, refuse
accord discord
accumulate disburse
accurate inaccurate
acquit condemn, convict
active passive, inactive
add subtract
admit deny
admire insult
advance retreat
advantage disadvantage
adversity prosperity
affirm deny
affection hatred
affirmative negative
affluence poverty, shortage
after before
afterwards presently
against for
aggravate alleviate, lessen
agree disagree, differ
alien native
alive dead
allies enemies, foes
 allow disallow, refuse
alone together
amplify simplify
always never
ancient modern
attractive repulsive
adorn disfigure
awake asleep
appreciate condemn, depreciate
arrogant humble
amateur professional
angry pleased
animate inanimate
antique modern
appear disappear
appoint dismiss
approval disapproval
arduous easy
arrive depart
artificial natural
asset liability
assemble disperse
atheism theism
attack defend
attach detach
atrocious mild
attraction repulsion
audacity timidity
auspicious inauspicious
autocracy  democracy 
back front
bad good
ban allow, permit
barbarous civilized
beautiful ugly
beginner expert
begin end, stop
behaviour misbehaviour
belief disbelief, doubt
belittle admire
benediction malediction
benevolent malevolent
biased unbiased
birth death
blame praise
blasphemous religious
blend sever
blunt sharp
bona fide bogus
boring interesting
borrow lend
bottom top
boon bane, curse
boisterous quiet, calm
brutal kindly, humane
bought sold
boycott accept
bravery cowardice
brevity loquacity
brittle strong
build demolish, destroy
busy lazy, idle
broad narrow
barren fertile
bondage  liberty
capture release
cancel rectify, accept
care neglect, negligence
careful careless
carry miscarry
cease begin
celebrated obscure
celibacy wedlock
certain uncertain
chaos order
civil rude, uncivil
cheap costly, dear
checked unchecked
cheerful gloomy, cheerless
chill warm
clear vague
clever stupid
closure disclosure, opening
coarse elegant
colourful colourless
comedy tragedy
compare contrast
competent incompetent
complete incomplete
compromising uncompromising
complicated simple
conceal reveal
concord discord
compact loose
conduct misconduct
confess deny
confidence non-confidence, diffidence
connect disconnect
conscious unconscious
certain uncertain
compulsory voluntary, optional
concise elaborate
concave convex
considerable negligible
consistency inconsistency
consumer producer
continue discontinue
contraction expansion
contrary agreeable
convenient inconvenient
converge diverge
convicted acquitted
convincing unconvincing
co-operation non-cooperation
correct incorrect, wrong
corrupt honest
consumption production
common uncommon
criminal innocent
chaste pure, unchaste
damp dry
decent indecent
darkness brightness, light
daunted undaunted
dangerous safe
dawn dusk
dead alive
debar allow
debit credit
debtor creditor
decrease increase
deep shallow
defence offence
deficit surplus
deflate inflate
deletion addition
deliberate unintentional
departure arrival
deposit withdraw
desirable undesirable
detain promote
difficult easy
dilate contract
dilute concentrated
direct indirect
discipline indiscipline
disclose hide
disorder order
disparity parity
disown own
disprove prove
dissuade persuade
distant near
distrust trust
diverge converge
discreet indiscreet
diversity unity
divisible indivisible
do undo
domestic wild
double single
down up
drain fill
dry wet
duplicate original
dwarf giant
dynamic static
discourage encourage
definite indefinite, vague
despair hope
docile stubborn
delicious bitter 
early late
earn spend
east west
ebb flow
eccentric normal
efficient inefficient
effeminate manly
elder younger
elevation depression
eliminate include
empty full
entrance exit
equality inequality
eternal temporal, fleeting
error accuracy
even uneven
exclude include
exhale inhale
expected unexpected
explicit implicit
export import
exterior interior
external internal
extrovert introvert
extravagant miserly, frugal
enrich impoverish
emancipate enslave
economy extravagance
ever  never
feeble strong
fickle steady, firm
fictitious real
finite infinite
fit unfit
flexible rigid/ inflexible
fold unfold
foolish wise, judicious
forbid allow
foreign native
fortunate unfortunate
frank secret
formal informal
former latter
forget remember
fame infamy
fickle constant
futility utility
fresh stale 
friend  foe, enemy
good  bad
goodwill  ill-will
grace  disgrace
gradual  sudden
gratitude  ingratitude
grave (n)  cradle
guest  host
guide  misguide
guilty  innocent
growth  decline
gain  loss
great ignominy
generous  stingy
great  small
harmony discord, disharmony
horizontal vertical
huge tiny, minute
hurt unhurt, heal
hypocrisy sincerity
honest dishonest
high low
hide reveal
honourable dishonourable
half full
handle mishandle
handsome ugly
hostility friendship
hither thither
hit miss
holy unholy
humble proud, haughty
hygienic unhygienic
hard soft
hind front
import export
indolent active, energetic
include exclude
industrious lazy
ill well
idealistic practical
idiot genius
ignoble noble
imaginary real
illiterate literate
illicit lawful
illogical logical
immortal mortal
imperfect perfect
improvement deterioration
income expense
individual general
indoor outdoor
infant adult
inferior superior
insert extract
integrate disintegrate
ignorant wise
input output
impatient outpatient
interior exterior
interpret misinterpret
introduction conclusion
invade defend
irritating pleasant
irregular  regular
join separate
jolly gloomy, sad, grave
joy sorrow
junior senior
justice injustice
juvenile senile
justify condemn
knowledge ignorance
kind cruel
keen blunt
kindle extinguish
laborious easy
last  first
landlord tenant
later earlier
large small
lavish miserly
lax strict
lead follow
lean fat
legal illegal
length breadth
liberal miserly
liberation enslavement
lessen add
liberty slavery
lie (n) truth
life death
light (n) darkness
light (adj) heavy
like dislike
liquid solid
load (v) unload
lock (v) unlock
love loathe, hate
long short
loosen tighten
logical illogical
loud low, silent
loyal disloyal
luck ill-luck
lukewarm zealous
luminous dull
lunacy sanity
luxurious frugal
mad sane
magnanimity meanness
major minor
male female
malign benign
mandatory optional
make mar
merit demerit, defect
moderate extremist
masculine feminine
marriage celibacy
mediocre excellent
master servant
maximum minimum
meek arrogant
mental physical
minimize magnify
minus plus 
miser spendthrift
mitigate aggravate
moist dry
momentary lasting
momentous trivial
monogamy polygamy
monologue dialogue
motley uniform
monism pluralism
mount dismount
movable immovable
native alien, foreign
naked clothed
natural artificial
nefarious lawful
neutral partial
new old
niggard spendthrift
notorious famous
nourish famish
nude dressed
numerous scanty
novice veteran
neat filthy, dirty 
obedient disobedient
obvious obscure
occasionally frequently
occidental oriental
occupy vacate
odd even
offer (v) refuse
often seldom
old young, new
on off
opaque transparent
optimism pessimism
opponent accomplice
oral written
outer inner
own disown
ominous auspicious
obstinate submissive
offensive defensive 
pack unpack
pardon punish
palatable unpalatable
parity disparity
parallel regular
part whole
partial impartial
permission refusal
public private, secret
pride humility
please displease, annoy
pure impure
prompt slow
punishment reward
precious cheap, worthless
praise condemn, blame
patient impatient
particular general
paucity abundance
pay receive
peace war
permanent temporary
persuade dissuade
personal impersonal
pioneer follower
pious impious
petulant polite
postpone expedite, advance
precede succeed
predecessor successor
presence absence
primary secondary
proceed recede
preliminary final
prefix suffix
professional amateur
profit loss
prologue epilogue
promote demote
proper improper
protest support
public  private
qualification disqualification
queer normal, common
quench inflame
quick slow
quiet noisy
quit remain 
quarrelsome  peaceful, friendly
radical orthodox
raise lower
radiance darkness
rare common
rash cautious
raw ripe
realistic unrealistic
rebellious loyal
rebuke praise
reckless cautions
refute support
rejoice grieve
reliable unreliable
reluctant willing, ready
remote near
renowned notorious
repel attract
recovery relapse
rude polite
relish dislike
relevant irrelevant
rural urban
ruthless merciful
repudiate affirm
rumour truth
reprimand compliment
rough smooth
rinse fall
retail wholesome
reverse forward
restive peaceful
rear front
rash cautious
restrain  incite 
sacred profane
saint sinner
salient secondary
sane insane
sanitary unsanitary
save squander
savoury unsavoury
scholar fool
scoff praise
screw unscrew
scrupulous unscrupulous
strict lax, lenient
same different
secure insecure
send bring
seize restore
sever unite
several few
shade light
 service disservice
sharp blunt
short long
shout whisper
silence noise
sin virtue
smart dull, stupid
smile frown
sound unsound
specific vague
speedy slow
sterile fertile
stout thin
strength weakness
strife peace
subjective objective
success failure
suffer withstand
summit base
sunrise sunset
supplier consumer
swell dwindle
sullen cheerful
support oppose
swift slow
sweet sour, bitter
synthetic natural
superior inferior
stiffness suppleness
sublime ridiculous
serious  trifling
tail head
tactful tactless
talkative reserved
taste distaste
tear stitch, patch,
temporary permanent
tender hard
theoretical practical
thesis antithesis
thrift extravagance
tidy untidy
tie untie
tight loose
timely untimely
top bottom
transient perpetual
terse diffuse
total partial
town village
tough yielding
transparent opaque
treachery loyalty
turbulent calm
ugliness loveliness
uncouth handsome
union separation
universal particular
urban rural
uniform variable 
vacant occupied, filled
valid invalid
vague clear
vanguard rearguard
vanity modesty
variable invariable
variety uniformity
vegetarian non-vegetarian
veracity  falsehood
wax wane
wakeful asleep
wealth poverty
weep laugh
wet dry
whole part
wicked virtuous
wide narrow
wild tame, domestic
wind (v) unwind
wisdom folly
withdraw advance, deposit
work rest
worse better
worst best
wrap unwrap
wrong right 
wit dullness
win lose
winsome ugly
yes no
yonder nearer
young old 
zenith nadir
zigzag straight