plenty vs copiousness

plenty and copiousness both are nouns.

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

As nouns, copiousness is a hypernym of plenty; that is, copiousness is a word with a broader meaning than plenty:

Other hypernyms of plenty include abundance, teemingness.

plenty (noun)	copiousness (noun)
a full supply	the property of a more than adequate quantity or supply
(often followed by `of') a large number or amount or extent

plenty (adverb)	copiousness (adverb)
as much as necessary