Feast is, I'd fancy, full (9)
I believe the answer is:
satisfied
'full' is the definition.
(thesaurus)
'feast is i'd fancy' is the wordplay.
'fancy' indicates anagramming the letters.
'feast'+'is'+'id'='feastisid'
'feastisid' anagrammed gives 'SATISFIED'.
(Other definitions for satisfied that I've seen before include "Convinced" , "Pleased, contented" , "Complied with (a condition)" , "relieved of doubt" , "given answer > was convincing" .)