Really, really dislike (4)
I believe the answer is:
hate
'really really dislike' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hate that I've seen before include "'Unimaginable as ---- in Heav'n': Milton" , "Antipathy" , "Strongly dislike" , "Thoroughly dislike, loathe" , "Passion" .)