Good to spread real bile (8)
I believe the answer is:
reliable
'good' is the definition.
(thesaurus)
'spread real bile' is the wordplay.
'spread' is an anagram indicator.
'real'+'bile'='realbile'
'realbile' anagrammed gives 'RELIABLE'.
'to' is the link.
(Other definitions for reliable that I've seen before include "Unfailing" , "Can be depended upon, trustworthy" , "Trusty" , "worthy of trust" , "Dependable, trustworthy" .)