Foul shot on the baize, maybe - or maybe not
I believe the answer is:
in-off
Can you help me to learn more?
(Other definitions for in-off that I've seen before include "Losing hazard at billiards" , "Error in game" , "Glancing billiards pot" , "Snooker hazard" , "Pot in billiards that hits another ball first" .)