Amiable fly in red soup (8)
I believe the answer is:
friendly
'amiable' is the definition.
(I've seen this before)
'fly in red soup' is the wordplay.
'soup' indicates anagramming the letters.
'fly'+'in'+'red'='flyinred'
'flyinred' with letters rearranged gives 'FRIENDLY'.
(Other definitions for friendly that I've seen before include "One is obviously on good terms with" , "Amiable" , "Affable" , "on the same side" , "Amicable, favourably disposed" .)