ogler vs viewer

ogler and viewer both are nouns.

Word	Noun	Adjective	Verb	Adverb
ogler	Yes	No	No	No
viewer	Yes	No	No	No

As nouns, viewer is a hypernym of ogler; that is, viewer is a word with a broader meaning than ogler:

ogler: a viewer who gives a flirtatious or lewd look at another person
viewer: a close observer; someone who looks at something (such as an exhibition of some kind)

Other hypernyms of ogler include looker, spectator, watcher, witness.

ogler (noun)	viewer (noun)
a viewer who gives a flirtatious or lewd look at another person	an optical device for viewing photographic transparencies
	a close observer; someone who looks at something (such as an exhibition of some kind)