Hate crime disheartened onlooker (5)
I believe the answer is:
abhor
'hate' is the definition.
(abhorring is a kind of hating)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for abhor that I've seen before include "can't stand" , "Find horrible" , "Execrate" , "Regard with repugnance" , "Hate or dislike intensely" .)