Friendly with a woolly-headed member (4)
I believe the answer is:
Here is my best explanation:
'friendly' is the definition.
('warm' can be a synonym of 'friendly')
'a woolly-headed member' is the subsidiary indication.
'a woolly-headed' becomes 'w' (this could be a standard abbreviation of which I'm unaware).
'member' becomes 'arm' (arm is a kind of member).
'with' is the link.
(Other definitions for warm that I've seen before include "Affectionate - balmy", "Pleasantly hot", "(Of a scent) fresh", "Getting close to target", "Heat", "Slightly hot", "Moderately hot", "Welcoming - getting close!", "Friendly" and "Enthusiastic".)