Rudely confident (5)
I believe the answer is:
brash
'rudely confident' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for brash that I've seen before include "Offensively showy" , "Cocky and tactless" , "loose broken rock" , "Crudely showy; bumptious" , "Brazen" .)