A girl accepts it as friendship (5)
I believe the answer is:
amity
'friendship' is the definition.
(I've seen this before)
'a girl accepts it' is the wordplay.
'a girl' becomes 'amy' ().
'accepts' is an insertion indicator.
'amy' enclosing 'it' is 'AMITY'.
'as' acts as a link.
(Other definitions for amity that I've seen before include "warmth" , "Friendliness" , "Friendship - goodwill" , "understanding" , "Cordiality" .)