quite vs quite an

quite and quite an both are adverbs.

Word	Noun	Adjective	Verb	Adverb
quite	No	No	No	Yes
quite an	No	No	No	Yes

As adverbs, quite and quite an are synonyms defined as:

quite and quite an: of an unusually noticeable or exceptional or remarkable kind (not used with a negative)

Other synonyms of quite include quite a.

quite (adverb)	quite an (adverb)
to the greatest extent; completely	of an unusually noticeable or exceptional or remarkable kind (not used with a negative)
to a degree (not used with a negative)
of an unusually noticeable or exceptional or remarkable kind (not used with a negative)
actually or truly or to an extreme