Master collie gently bites (5)
I believe the answer is:
liege
'master' is the definition.
(I know that liege is a type of feudatory)
'collie gently bites' is the wordplay.
'bites' indicates a hidden word (the answer has been bitten or eaten by the clue).
'LIEGE' can be found hidden inside 'collie gently'.
(Other definitions for liege that I've seen before include "Belgian city - master - servant" , "Vassal, subject" , "Sort of lord" , "old lord" , "Belgian city or ancient superior" .)