Quite upset somebody that I don't like (6)
I believe the answer is:
enough
'quite' is the definition.
'upset somebody that i don't like' is the wordplay.
'upset' says the letters should be written in reverse.
'somebody' becomes 'one' (I've seen this in other clues).
'that i don't like' becomes 'ugh' (exclamation of disgust).
'one' written backwards gives 'eno'.
'eno'+'ugh'='ENOUGH'
(Other definitions for enough that I've seen before include "satisfying" , "As much as desired" , "Stop right now!" , "Adequate, sufficient" , "Ample, sufficient" .)