swing for

From the sense of "swing" meaning to be hung by the neck, for murder.

swing for (third-person singular simple present swing for, present participle swing for, simple past and past participle swung for)

1. Implies that the one party will murder the other, and as a result "swing". Often hyperbolic. Archaic.

   I'll swing for him, when I get out. Katherine Lynch reported in “Minor Matters: Willing to "Swing for Him."”, in Weekly Mail‎, Cardiff, 20 June 1908, page 10

• forswing