Hatred? An extreme point attendant on extremes of hostility (9)
I believe the answer is:
'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'.
(Other definitions for antipathy that I've seen before include "deep-seated dislike" , "Abhorrence" , "Feeling of deep aversion" , "ill will" , "Hostility - hint at pay (anag)" .)