Very fashionable (4)
'very fashionable' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for trendy that I've seen before include "Up to date, fashionable" , "Stylish" , "Consciously fashionable" , "Voguish" , "With it, a la mode" .)
(Other definitions for chic that I've seen before include "Fashionably smart" , "Fashionable good taste" , "Stylishness, elegance" , "Trendy" , "French elegance" .)