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
British Dictionary definitions for clincher
Word Origin and History for clincher
early 14c., "person or thing that clinches" (i.e., secures nails by bending down or riveting the pointed end), late 15c. as a class of shipyard worker; agent noun from clinch (v.). As a type of nail, from 1735; as a conclusive statement, argument, etc., 1737.