Boastful threatening (7)
I believe the answer is:
bravado
'boastful threatening' 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" , "Boldness intended to impress" , "Swaggering show of boldness" , "showing off" , "Swaggering show of false courage" .)