Warm fly in red soup (8)
I believe the answer is:
friendly
'warm' is the definition.
(synonyms)
'fly in red soup' is the wordplay.
'soup' indicates anagramming the letters.
'fly'+'in'+'red'='flyinred'
'flyinred' anagrammed gives 'FRIENDLY'.
(Other definitions for friendly that I've seen before include "Affable" , "such a society" , "match?" , "Well-disposed" , "prepared to talk to fellow passengers?" .)