The use of dingleberry to refer to a rectum-clinging piece of feces has been attested since the 1920s. The origin of this meaning isn't clear. It may be based on dangle or dingbat. It's no big leap from dingleberry as a small piece of turd stuck the butt to an insult for someone considered foolish or inept.

Where did the name dingleberry come from?

Scottish annals reveal that the Dingleberry surname came from a place name in Scotland, named with Viking elements. The name was no doubt taken on when they lived at Royal Burgh of Dingwall, in Ross-shire, Scotland. The place-name is derived from the Old English word dingle, which meant valley or hollow.

What does it mean when you call someone a dingleberry?

1 US, informal : a foolish, stupid, or contemptible person Something about human nature makes us all think we are the best drivers on the road at any given time. It's everyone else who are the dingleberries.—