Hem's partner (3)
I believe the answer is:
haw
'hem's partner' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for haw that I've seen before include "Fruit of common thorn tree (3)" , "Hem and . . . - grope for words" , "Small red berry of a thorny tree" , "Hedgerow fruit" , "Fruit of a thorny bush" .)