The most common and most likely answer to this crossword clue is the 6 letter word DUNCES
D
U
N
C
E
S
Buddy explains!

The straight part
We know that "Idiots" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case idiots = dunces.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.
What does DUNCES mean?
DUNCES noun- An unintelligent person.