Examples from the Web for clincher
This was a clincher—assorted worthies sent their own medals back in protest but everyone else was delighted.What It Was Like to Watch the Beatles Become the Beatles—Nik Cohn Remembers|Nik Cohn|February 9, 2014|DAILY BEAST
Conclusive as this argument is, there is yet another in reserve, which is a clincher.
But the clincher is those two sugar crystals Lloyd had grabbed up when we were in that zoo.The Dope on Mars|John Michael Sharkey
The last remark was intended as a clincher to settle the affair.True Blue|W.H.G. Kingston
That clincher has gone to the place whither good clinchers go, forever.
Clincher, that which rivets or confirms an argument, an incontrovertible position.The Slang Dictionary|John Camden Hotten