Ancient city pub’s entered for award (6)
I believe the answer is:
trophy
'for award' is the definition.
(trophy is a kind of award)
'ancient city pub's entered' is the wordplay.
'ancient city' becomes 'troy' (Troy was an ancient city).
'pub' becomes 'ph' (abbreviation).
'entered' is an insertion indicator.
'troy' going around 'ph' is 'TROPHY'.
(Other definitions for trophy that I've seen before include "Cup, say, awarded as a prize for victory or success" , "Winner's prize" , "Scalp - memento" , "Laurels" , "Memorial of victory" .)