calm - windy, troubled
can - cannot, can't
capable - incapable
captive - free
careful - careless
cheap - expensive
cheerful - sad, discouraged, dreary
clear - cloudy, opaque
clever - stupid
clockwise - counterclockwise
close - far, distant
closed - ajar, open
clumsy - graceful
cold - hot
combine - separate
come - go
comfort - discomfort
common - rare
conceal - reveal
contract - expand
cool - warm
correct - incorrect, wrong
courage - cowardice
create - destroy
crooked - straight
cruel - kind
compulsory - voluntary
courteous - discourteous, rude
can - cannot, can't
capable - incapable
captive - free
careful - careless
cheap - expensive
cheerful - sad, discouraged, dreary
clear - cloudy, opaque
clever - stupid
clockwise - counterclockwise
close - far, distant
closed - ajar, open
clumsy - graceful
cold - hot
combine - separate
come - go
comfort - discomfort
common - rare
conceal - reveal
contract - expand
cool - warm
correct - incorrect, wrong
courage - cowardice
create - destroy
crooked - straight
cruel - kind
compulsory - voluntary
courteous - discourteous, rude