Be warm-hearted in support (4)
I believe the answer is:
bear
'support' is the definition.
(I know that support can be written as bear)
'be warm-hearted' is the wordplay.
'hearted' says to take the centre.
The middle letters of 'warm' are 'ar'.
'be'+'ar'='BEAR'
'in' is the link.
(Other definitions for bear that I've seen before include "someone being ill-mannered" , "It could be polar or grizzly" , "Situation where there are more sellers than willing buyers" , "Put up with - beast!" , "It may be polar or grizzly" .)