Acted boldly (5)
I believe the answer is:
dared
'acted boldly' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dared that I've seen before include "Had the courage (to do something)" , "Made bold" , "Challenged - was audacious" , "was bold enough" , "Challenged (to a deed)" .)