Outside of tweedy coats tear with it (6)
I believe the answer is:
trendy
'with it' is the definition.
(both can mean fashionable)
'outside of tweedy coats tear' is the wordplay.
'outside of' suggests removing the centre.
'coats' means one lot of letters goes inside another (inserted letters are coated in another word).
'tear' becomes 'rend' (rending is a kind of tearing).
'tweedy' with its centre taken out is 'ty'.
'ty' enclosing 'rend' is 'TRENDY'.
(Other definitions for trendy that I've seen before include "Informally, following the fashions" , "Smart" , "following fashion" , "'Hip, fashionable (6)'" , "Stylish" .)