Green’s Dictionary of Slang

clinch v.

[SE clinch]

1. to embrace sexually.

1728
17501800185019001950
1965
[[UK]J. Dalton Narrative of Street-Robberies 51: Falling in Company with one Moll Clincher, at a Brandy-Shop, she persuaded him to go with her to Chelsea, where she would entertain him].
[US]Ade Fables in Sl. 26: George was sitting on the Front Porch with a good Side Hold on Mabel [...] While they were Clinched, Mabel’s Father [...] came down the Stairway and out to the Veranda.
[US]Ade Forty Modern Fables 96: All the Married Couples would Clinch at the Hotel Steps.
[US]H.C. Witwer Yes Man’s Land 100: A lot of close-ups was took of Calhoun in a football outfit clinching with Fay.
[US]W. Smitter F.O.B. Detroit 37: ‘My snookie-um-u-m-m-ums.’ They clinched.
[US]G. Swarthout Where the Boys Are 178: Tuggle and Quentin clinching.
[UK]J.P. Carstairs Concrete Kimono 36: We clinched.

2. to catch, to arrest.

1852
1860187018801890
1895
[UK]Kendal Mercury 17 Apr. 6/1: But at last he vas clinched, and bound fast in the start.
[Aus]Crowe Aus. Sl. Dict. 18: Clinch, to be imprisoned.

3. to shake hands.

[US]F.P. Dunne in Schaaf Mr Dooley’s Chicago (1977) 81: An’ with that they clinched.