German article features fashionable restaurant (5)
I believe the answer is:
diner
'restaurant' is the definition.
(diner is a kind of restaurant)
'german article features fashionable' is the wordplay.
'german article' becomes 'der' (definite article in German).
'features' indicates putting letters inside.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'der' placed around 'in' is 'DINER'.
(Other definitions for diner that I've seen before include "Small US restaurant" , "Eater" , "Restaurant client" , "(Person eating in) restaurant" , "(One using) restaurant car" .)