Billiards shot that goes into a pocket after striking another ball (2-3)
I believe the answer is:
in-off
(Other definitions for in-off that I've seen before include "Pot in billiards that hits another ball first" , "Snooker hazard" , "Indirect billiards shot" , "Type of cannon in billiards" , "Foul (snooker), scoring stroke (billiards)" .)