Attempt to cover rear with it? (6)
I believe the answer is:
trendy
'with it?' is the definition.
(thesaurus)
'attempt to cover rear' is the wordplay.
'attempt' becomes 'try' (I've seen this before).
'to cover' indicates putting letters inside.
'rear' becomes 'end' (I've seen this in other clues).
'try' enclosing 'end' is 'TRENDY'.
(Other definitions for trendy that I've seen before include "Modish" , "Smart" , "following latest convention" , "Stylish" , "With-it" .)