Can a word be a ANTONYM has well has a SYNONYM.?

Feline isn't exactly a synonym to cat. Feline is a more scientific term for a cat. Girl and Woman are considered different STAGES of Female, much like boy and man are different stages of males. Hot and Spicy can be considered synonyms. I'm sure there are websites that would help you with it, but it's really more how you specifically define the terms I guess.