Wiktionary
diddly-squat
n. (context US slang often humorous English) nothing; nothing whatsoever.
WordNet
diddly-squat
n. a small worthless amount; "you don't know jack" [syn: jack, diddlysquat, diddly-shit, diddlyshit, diddly, diddley, squat, shit]
Usage examples of "diddly-squat".
But I'll get over it in time, and when I do, well, there's not diddly-squat for me in Colonial Pines.
You can tell her or not-it doesn't make diddly-squat to me-but if I don't get that money by tonight, I go to the sheriff tomorrow, and you'll be in the street by the end of the week.