Hear about object, very fashionable (6)
I believe the answer is:
trendy
'very fashionable' is the definition.
(I've seen this before)
'hear about object' is the wordplay.
'hear' becomes 'try' (to hear or try a case in the legal sense).
'about' is an insertion indicator.
'object' becomes 'end' (I've seen this in other clues).
'try' placed around 'end' is 'TRENDY'.
(Other definitions for trendy that I've seen before include "In accordance with the latest fad" , "In fashion, of popular style" , "Hot" , "Fashionable, in style" , "Informally fashionable" .)