Lane doesn’t have a bit of enmity for friend (4)
I believe the answer is:
ally
'friend' is the definition.
(synonyms)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for ally that I've seen before include "Cooperating country" , "A friendly and reliable country" , "couple?" , "Confederate; supporter" , "Team up" .)