The Random House Historical Dictionary of American Slang suggests that this is a variation of doodly-squat from 1934. Doodly-squat was originally the more common form, but diddly-squat overtook it in the mid-1970s, and is now four times more common in print.
- (US slang, often humorous) Nothing; nothing whatsoever.
- Synonyms: see Thesaurus:nothing
- 2004, Barbara Sutton, The Send-away Girl: Stories, University of Georgia Press (→ISBN), page 184:
- I didn't know diddly-squat about development; I also didn't know that someone could be an “officer” of major gifts. “Do they wear badges?” my friends had wanted to know, because my friends, like myself, had been completely ignorant of the field of development.
- 2007, Chris Stewart, The Fourth War, Macmillan (→ISBN)
- Money? Power? Maybe a little prestige? Everything they worked for amounted to diddly-squat; more money, bigger houses, more and more empty air. None of them would ever know the feeling of having a purpose in life.