Sceptic hates it being wrong (7)
I believe the answer is:
atheist
'sceptic' is the definition.
(I've seen this before)
'hates it being wrong' is the wordplay.
'being wrong' indicates an anagram.
'hates'+'it'='hatesit'
'hatesit' with letters rearranged gives 'ATHEIST'.
(Other definitions for atheist that I've seen before include "Non-believer in god - hates it (anag)" , "Person who does not believe in existence of a god" , "One who believes there is no god" , "Someone who denies the existence fo God" , "One who does not believe in the existence of a god" .)