kitty vs kitty-cat

kitty and kitty-cat both are nouns.

Word	Noun	Adjective	Verb	Adverb
kitty	Yes	No	No	No
kitty-cat	Yes	No	No	No

As nouns, kitty and kitty-cat are synonyms defined as:

Other synonyms of kitty include puss, pussy, pussycat.

kitty (noun)	kitty-cat (noun)
informal terms referring to a domestic cat	informal terms referring to a domestic cat
young domestic cat
the combined stakes of the betters
the cumulative amount involved in a game (such as poker)