Spiteful person breaking heart (5)
I believe the answer is:
hater
'spiteful person' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe there's an association between them I don't understand?
'breaking heart' is the wordplay.
'breaking' indicates an anagram.
'heart' anagrammed gives 'HATER'.
Can you help me to learn more?
(Other definitions for hater that I've seen before include "He loathes" , "One loathing" , "Person showing animosity" , "Heart (anag.)" , "I really can't stand" .)