critter sitter vs custodian

critter sitter and custodian both are nouns.

Word	Noun	Adjective	Verb	Adverb
critter sitter	Yes	No	No	No
custodian	Yes	No	No	No

As nouns, custodian is a hypernym of critter sitter; that is, custodian is a word with a broader meaning than critter sitter:

critter sitter: someone left in charge of pets while their owners are away from home
custodian: one having charge of buildings or grounds or animals

Other hypernyms of critter sitter include keeper, steward.

critter sitter (noun)	custodian (noun)
someone left in charge of pets while their owners are away from home	one having charge of buildings or grounds or animals