Felt wrong, not right! (4)
I believe the answer is:
left
'not right' is the definition.
('left' is the opposite to 'right')
'felt wrong' is the wordplay.
'wrong' indicates an anagram.
'felt' anagrammed gives 'LEFT'.
(Other definitions for left that I've seen before include "Allowed to remain" , "It's not right" , "Socialist direction" , "Went; port" , "split" .)