mountain vs plenty

mountain and plenty both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain	Yes	No	No	No
plenty	Yes	No	No	Yes

As nouns, mountain and plenty are synonyms defined as:

mountain and plenty: (often followed by `of') a large number or amount or extent

mountain (noun)	plenty (noun)
a land mass that projects well above its surroundings; higher than a hill	a full supply
(often followed by `of') a large number or amount or extent	(often followed by `of') a large number or amount or extent

mountain (adverb)	plenty (adverb)
	as much as necessary