peeper vs watcher

peeper and watcher both are nouns.

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

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

peeper: a viewer who enjoys seeing the sex acts or sex organs of others
watcher: a close observer; someone who looks at something (such as an exhibition of some kind)

Other hypernyms of peeper include looker, spectator, viewer, witness.

peeper (noun)	watcher (noun)
an animal that makes short high-pitched sounds	a guard who keeps watch
an informal term referring to the eye	a close observer; someone who looks at something (such as an exhibition of some kind)
a viewer who enjoys seeing the sex acts or sex organs of others	a person who keeps a devotional vigil by a sick bed or by a dead body