Ally, companion (7)
I believe the answer is:
partner
I believe this clue is a double definition.
'ally' is the first definition.
(I've seen this before)
'companion' is the second definition.
(I've seen this before)
(Other definitions for partner that I've seen before include "Professional colleague" , "Spouse or business collaborator" , "Either member of a couple" , "Ally" , "Companion at bridge, dance, or home" .)