Charming pub in annexe (7)
I believe the answer is:
winning
'charming' is the definition.
(thesaurus)
'pub in annexe' is the wordplay.
'pub' becomes 'inn' (an inn is a type of pub).
'in' means one lot of letters goes inside another.
'annexe' becomes 'wing' (synonyms).
'inn' placed into 'wing' is 'WINNING'.
(Other definitions for winning that I've seen before include "collecting cash?" , "Appealing" , "Attractive; coming top" , "Persuasive; on top" .)