Impressive boldness (7)
I believe the answer is:
bravado
'impressive boldness' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for bravado that I've seen before include "Vaunted courage" , "Showy boldness" , "Boastful show" , "Show of bravery" , "A show of boldness or bluster" .)