Opposite of fat
thin
Opposite of dirty
clean
Opposite of dry
wet
Opposite of healthy
sick / ill
Opposite of full
hungry
Opposite of poor
rich / wealthy
Opposite of happy
sad
Opposite of expensive
cheap
Opposite of short
tall
Opposite of strong
weak
Opposite of delicious
awful
Opposite of soft
hard
Opposite of cold
hot
Opposite of bitter
sweet
Opposite of old
young
Opposite of hard-working
lazy
Opposite of curly
straight
Opposite of modern
ancient
Opposite of beautiful
ugly
Opposite of slow
fast