Green’s Dictionary of Slang

1. a fiery drink (cf. knock-me-down n.).

1515

De Generibus Ebriosorum etc. J.E.Hodgkin in N&Q Ser. 3 VII 163: The catalogue which follows shows that even the names of fancy drinks are not new [...]: Cow’s-tail, Calve’s-neck, Buffalo, Slip-slop, Stamp-in-the-Ashes, Knock-’em-down [F&H].

2. an act of violence.

2007

S. Maloney Sucked In 267: The Age described the casino event as ‘a hoop-la [...] ’ The knock-’em-downs didn’t get a mention [...] The lid was on and that’s where I hoped it stayed.