early 14c., lins, from Old English lynis “linchpin,” from Proto-Germanic *luniso (cf. Old Saxon lunisa, Middle Dutch lunse, Dutch luns, German Lünse).
Examples from the Web for linch Historical Examples of linch
The dissentient, Bristed, says that to linch is in various northern English dialects, and means to beat or maltreat.
Henry L. Mencken