sad-happy
sadness-happiness
safe-dangerous
safety-danger
salt-sugar
same-different
satisfaction-regret
satisfy-annoy
save-spend
scream-whisper
security-danger
seldom-often
sell-buy
send-receive
senior-junior
separate-connect
serious-funny
servant-master
set free-arrest
shallow-deep
sharp-blunt
shelter-exposure

short – long
shout – whisper
shut – open
sick – healthy
silent – noisy
silly – intelligent
simple – complicated
sink – rise
single – married
sister – brother
sit – stand
slim – fat
slow – fast
small – big
smooth – rough
soft – hard
solid – liquid
some – many
sometimes – often
son – daughter
soul – body
sour – sweet

south – north
special – general
spring – autumn
stand – sit
start – stop
start – finish
stop – start
stand – lie
strange – normal
stranger – native
strict – gentle
strong – weak
student – teacher
stupid – clever
suburb – centre
succeed – fail
success – failure
subtract – add
sugar – salt
summer – winter
sun – moon
sunny – cloudy