spectator vs viewer

spectator and viewer both are nouns.

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

As nouns, spectator and viewer are synonyms defined as:

spectator and viewer: a close observer; someone who looks at something (such as an exhibition of some kind)

Other synonyms of spectator include looker, watcher, witness.

spectator (noun)	viewer (noun)
a woman's pump with medium heel; usually in contrasting colors for toe and heel	an optical device for viewing photographic transparencies
a close observer; someone who looks at something (such as an exhibition of some kind)	a close observer; someone who looks at something (such as an exhibition of some kind)