Colleague in compound being loveless (4)
I believe the answer is:
ally
'colleague' is the definition.
(ally can mean a colleague or associate)
I don't understand how the rest of the clue works.
(Other definitions for ally that I've seen before include "Friend and colleague" , "Join by marriage, treaty etc" , "He fights on your side" , "Associate that provides assistance" , "Crony" .)