Any confusion is negative (3)
I believe the answer is:
nay
'is negative' is the definition.
(I've seen this before)
'any confusion' is the wordplay.
'confusion' indicates an anagram.
'any' anagrammed gives 'NAY'.
(Other definitions for nay that I've seen before include "telling a nicker from a pony?" , "Negative response" , "disagreement" , "even" , "Indeed" .)