Daredevil to shock a thousand brown bears (5,3)
I believe the answer is:
stunt man
'daredevil' is the definition.
(thesaurus)
'shock a thousand brown bears' is the wordplay.
'shock' becomes 'stun' ('stun' can be a synonym of 'shock'**).
'a thousand' becomes 'm' ('M' can be a synonym of 'thousand').
'brown' becomes 'tan' (tan is a kind of brown).
'bears' means one lot of letters goes inside another.
'm' going within 'tan' is 'tman'.
'stun'+'tman'='STUNT MAN'
'to' acts as a link.
(Other definitions for stunt man that I've seen before include "Actor's stand-in" , "Person employed to do difficult feats for actors" , "Performer of dangerous acts in films etc" , "Movie extra who performs dangerous feats" , "Danger stand-in" .)