1 informal : an often small article whose common name is unknown or forgotten : gadget, doodad sense 2
2 US slang : a dim-witted, silly, or foolish person —often used in a joking or friendly way
First Known Use of dingus
1873, in the meaning defined at sense 1
History and Etymology for dingus
Dutch or German; Dutch dinges, probably from German Dings, from genitive of Ding thing, from Old High German — more at thing