Fashionable attempt to cover rear (6)
I believe the answer is:
trendy
'fashionable' is the definition.
(similar in meaning)
'attempt to cover rear' is the wordplay.
'attempt to' becomes 'try' (I've seen this in other clues).
'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 "following fashion" , "In accordance with the latest fad" , "Informally, following the fashions" , "With-it" , "Informally fashionable" .)