While researching something unrelated I found this entry on Etymonline:
an idiot sometimes became a nidiot, which, with still-common casual pronunciation, became nidget, which, alas, has not survived.
Is it true that the "nidget" has not survived?
Friends of mine from Dublin and Liverpool (both sadly long dead, so I cannot ask them) used to use the word, I am quite sure, with regularity when discussing the deficiencies of neighbours, relatives, and most often, politicians.
Are there some dialects that still make use of this variant of an idiot, or have I outlived yet another word?