flunky vs retainer

flunky and retainer both are nouns.

Word	Noun	Adjective	Verb	Adverb
flunky	Yes	No	No	No
retainer	Yes	No	No	No

As nouns, retainer is a hypernym of flunky; that is, retainer is a word with a broader meaning than flunky:

flunky: a male servant (especially a footman)
retainer: a person working in the service of another (especially in the household)

Other hypernyms of flunky include servant.

flunky (noun)	retainer (noun)
a person of unquestioning obedience	a dental appliance that holds teeth (or a prosthesis) in position after orthodontic treatment
a male servant (especially a footman)	a person working in the service of another (especially in the household)
	a fee charged in advance to retain the services of someone