Hem partner (3)
I believe the answer is:
haw
'hem partner' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for haw that I've seen before include "A blackthorn berry" , "Fruit of a thorny bush" , "Berry of a thorny shrub" , "Fruit of the may tree" , "Small red berry of a thorny tree" .)