zoo keeper vs keeper

zoo keeper and keeper both are nouns.

Word	Noun	Adjective	Verb	Adverb
zoo keeper	Yes	No	No	No
keeper	Yes	No	No	No

As nouns, keeper is a hypernym of zoo keeper; that is, keeper is a word with a broader meaning than zoo keeper:

Other hypernyms of zoo keeper include custodian, steward.

zoo keeper (noun)	keeper (noun)
the chief person responsible for a zoological garden	one having charge of buildings or grounds or animals
	someone in charge of other people