Green’s Dictionary of Slang

jam v.1

[one’s head is ‘jammed’ into the noose; ? ref. to the original method of hanging, jamming the neck into a forked piece of wood]

to hang; usu. as jammed adj.1

[UK]G. Stevens ‘A Cant Song’ Muses Delight 177: She said I must love you, you’re quiddish and bold, / You shall doss with me Jemmy till jamming.

In compounds

jamming cull (n.)

(UK und.) a hangman.

[UK]Proc. Old Bailey 2 May 82/1: As soon as he saw him, [he] said to a Gentleman that stood by him, - here comes the Jamming Cull, (meaning the Man that was to hang him).