peeper vs beast

peeper and beast both are nouns.

Word	Noun	Adjective	Verb	Adverb
peeper	Yes	No	No	No
beast	Yes	No	No	No

As nouns, beast is a hypernym of peeper; that is, beast is a word with a broader meaning than peeper:

Other hypernyms of peeper include animal, animate being, brute, creature, fauna.

peeper (noun)	beast (noun)
an animal that makes short high-pitched sounds	a living organism characterized by voluntary movement
an informal term referring to the eye	a cruelly rapacious person
a viewer who enjoys seeing the sex acts or sex organs of others