Become friendlier (4)
I believe the answer is:
thaw
'become friendlier' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for thaw that I've seen before include "end of the winter?" , "What - melt like snow?" , "following 28 [SILVER]" , "(Of snow) start to melt" , "Become less stiff, more relaxed" .)