Worst cry of pain to give (6)
I believe the answer is:
bestow
'to give' is the definition.
(bestowing is a kind of giving)
'worst cry of pain' is the wordplay.
'worst' becomes 'best' (both can mean to beat someone).
'cry of pain' becomes 'ow' (exclamation of pain).
'best'+'ow'='BESTOW'
(Other definitions for bestow that I've seen before include "Confer or award" , "'Confer, present (6)'" , "Confer (an honour)" , "Present, donate" , "Award, present as a gift" .)