cheerer vs viewer

cheerer and viewer both are nouns.

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

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

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

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

cheerer (noun)	viewer (noun)
a spectator who shouts encouragement	an optical device for viewing photographic transparencies
	a close observer; someone who looks at something (such as an exhibition of some kind)