Urban Dictionary doesn’t yet have a definition for the specific “word” doodlum and the closest to the “word” I can find is Doodly-squat which has very nearly the meaning I associate with “doodlum” or “doodlum squat” from my memory. Most likely the difference is regional at least if not just a variant in the town where I was a kid.
Just curious if anybody else can attest to the usage(s) of doodlum in their own past.
I’m from the lower Appalachian hills which was primarily settled by Scots Irish. Doodlum squat and diddly squat were used quite often then. Some folks there still say it.