Brashly presumptuous (5)
I believe the answer is:
pushy
'brashly presumptuous' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pushy that I've seen before include "Overly assertive" , "Informally aggressive, not patient" , "Excessively self-assertive" , "Self-assertive, forceful" , "Socially aggressive" .)