Ambush — hazard of course (4)
I believe the answer is:
trap
This clue is a double definition.
'ambush' is the first definition.
(synonyms)
'hazard of course' is the second definition.
(US term for bunker, type of golf course hazard)
(Other definitions for trap that I've seen before include "The Web" , "get in net" , "Confine" , "Rock; carriage; gin" , "Catch; two-wheeled carriage" .)