pussycat vs doer

pussycat and doer both are nouns.

Word	Noun	Adjective	Verb	Adverb
pussycat	Yes	No	No	No
doer	Yes	No	No	No

As nouns, doer is a hypernym of pussycat; that is, doer is a word with a broader meaning than pussycat:

Other hypernyms of pussycat include actor, worker.

pussycat (noun)	doer (noun)
informal terms referring to a domestic cat	a person who acts and gets things done
a person who is regarded as easygoing and agreeable