Outlaw posed scruffily keeping challenge to return (9)
I believe the answer is:
desperado
'outlaw' is the definition.
(desperado is a kind of outlaw)
'posed scruffily keeping challenge to return' is the wordplay.
'scruffily' is an anagram indicator.
'keeping' means one lot of letters goes inside another.
'challenge' becomes 'dare' (daring is a kind of challenging**).
'to return' says the letters should be written in reverse.
'dare' backwards is 'erad'.
'posed' anagrammed gives 'despo'.
'despo' placed around 'erad' is 'DESPERADO'.
(Other definitions for desperado that I've seen before include "Bold outlaw on the American frontier" , "Reckless guy" , "Bandit, outlaw" , "Reckless criminal" , "Gangster" .)