tidy sum vs mess

tidy sum and mess both are nouns.

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

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

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

tidy sum (noun)	mess (noun)
(often followed by `of') a large number or amount or extent	a (large) military dining room where service personnel eat or relax
	a meal eaten in a mess hall by service personnel
	soft semiliquid food
	(often followed by `of') a large number or amount or extent
	a state of confusion and disorderliness
	informal terms for a difficult situation

tidy sum (verb)	mess (verb)
	make a mess of or create disorder in
	eat in a mess hall