Hatred? An extreme point attendant on extremes of hostility (9)
I believe the answer is:
Here is my best explanation:
'hatred?' is the definition.
'an extreme point attendant on extremes of hostility' is the wordplay.
'extreme point' becomes 'tip'.
'attendant on' becomes 'at'.
'extremes of' suggests removing the centre.
'hostility' with its centre removed is 'hy'.