moviegoer vs viewer

moviegoer and viewer both are nouns.

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

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

moviegoer: someone who goes to see movies
viewer: a close observer; someone who looks at something (such as an exhibition of some kind)

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

moviegoer (noun)	viewer (noun)
someone who goes to see movies	an optical device for viewing photographic transparencies
	a close observer; someone who looks at something (such as an exhibition of some kind)