clincher

noun

1. That which clinches; that which makes something final or firm; a decisive factor.

   “The clincher was that we couldn't wait any longer to leave, or it would get dark.”

   “Newcastle's Dan Gosling was sent off for a foul on Russell Martin but Ba fired in to cut the deficit, before Holt nodded in the clincher.”

   “Even after what turned out to be the clincher, Hakim Ziyech, Kai Havertz and Jorginho went close to forcing a penalty shootout.”

   “Transport Scotland acknowledges that the permanence of the new fares regime could be the clincher in persuading people to "travel more often and make long-term choices with certainty, helping people to leave the car at home".”

2. A tyre with a bead around the edge to attach to the rim of the wheel when inflated.