Outstanding feature of church fenced in by popular duke (8)
I believe the answer is:
inspired
'outstanding' is the definition.
(inspired can mean outstanding or excellent)
'feature of church fenced in by popular duke' is the wordplay.
'feature of church' becomes 'spire' (part of a church building).
'fenced in' indicates putting letters inside (I've seen this in other clues).
'by' is a charade indicator (letters next to each other).
'popular' becomes 'in' ('in' can mean trendy).
'duke' becomes 'd' (abbreviation).
'in'+'d' is 'ind'.
'spire' placed within 'ind' is 'INSPIRED'.
(Other definitions for inspired that I've seen before include "Encouraged" , "Brilliant (guess); aroused" , "Having a suddenly brilliant idea" , "Dazzling" , "Stimulated to excellence" .)