Newspaper introducing excellent feature (5)
I believe the answer is:
facet
'feature' is the definition.
(I know that facet is a type of feature)
'newspaper introducing excellent' is the wordplay.
'newspaper' becomes 'FT' (Financial Times newspaper).
'introducing' is an insertion indicator (some letters introduced or inserted into others).
'excellent' becomes 'ace' (I've seen this before).
'ft' enclosing 'ace' is 'FACET'.
(Other definitions for facet that I've seen before include "Small flat surface of cut gemstone" , "Side or surface, diamond or building" , "Aspect - smooth cut surface" , "(Gem) side; aspect" , "Particular aspect" .)