plenty vs tidy sum

plenty and tidy sum both are nouns.

Word	Noun	Adjective	Verb	Adverb
plenty	Yes	No	No	Yes
tidy sum	Yes	No	No	No

As nouns, plenty and tidy sum are synonyms defined as:

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

plenty (noun)	tidy sum (noun)
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

plenty (adverb)	tidy sum (adverb)
as much as necessary