diddly-shit vs diddly-squat

diddly-shit and diddly-squat both are nouns.

Word	Noun	Adjective	Verb	Adverb
diddly-shit	Yes	No	No	No
diddly-squat	Yes	No	No	No

As nouns, diddly-shit and diddly-squat are synonyms defined as:

Other synonyms of diddly-shit include diddley, diddly, diddlyshit, diddlysquat, doodly-squat, jack, shit, squat.

diddly-shit (noun)	diddly-squat (noun)
a small worthless amount	a small worthless amount