Curse hate without limits (4)
I believe the answer is:
oath
'curse' is the definition.
(synonyms)
'hate without limits' is the wordplay.
'hate' becomes 'loathe' (loathing is a kind of hating).
'without limits' means to look at the middle letters (letters at the edges or 'limits' are removed).
The central letters of 'loathe' are 'OATH'.
(Other definitions for oath that I've seen before include "Solemn vow" , "It could be ruddy when minced" , "A word with a witness" , "Swearword, expletive" , "Swearword or solemn promise" .)