The most common and most likely answer to this crossword clue is the 4 letter word BERK
B
E
R
K
More clues leading to the result BERK
Buddy explains!
The straight part
We know that "Idiot" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case idiot = berk.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
Crossword Answer definitions
BERK noun- (sometimes affectionate) A fool, prat, twit.
- Cunt.