Go-getter husband headed off cattle thief (7)
I believe the answer is:
hustler
'go-getter' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for hustler that I've seen before include "Illicit dealer (mainly US)" , "Energetic or crooked operator" , "Aggressive seller" , "Aggressive dealer" , "The slur (anag)" .)