Adventurous or audaciously bold (6)
I believe the answer is:
daring
This clue is a double definition.
'adventurous' is the first definition.
(similar in meaning)
'audaciously bold' is the second definition.
(I've seen this before)
(Other definitions for daring that I've seen before include "rash" , "Audacious, bold" , "Bold, willing to take chance" , "A grind (anag.)" , "Boldly dramatic or unconventional" .)