What is an antonym?

An antonym is a word meaning the opposite of another word.

What is an antonym of cat?  Think about this one.  I'll give you a clue, you might know him better as Odie.  If you said dog, you are right!  Let's try some more!

An antonym of girl

is boy.

An antonym of messy

is neat.

An antonym of young

is old.

An antonym of sun

is moon.

An antonym of hot

is cold.