Green’s Dictionary of Slang

1. in lit. or fig. use, a knockout blow; often ext. as old one-two, the under old adj.; also as v. to hit in this manner.

1819		‘One of the Fancy’ Tom Crib’s Memorial to Congress 14: Which t’other observing put in his ONE-TWO / Between GEORGY’S left ribs, with a knuckle so true.
1822		American (N.Y.) 2 Mar. 2/3: [signatures to a letter purportedly written by two boxers] ONE TWO and FLOORER.
1825		Pierce Egan’s Life in London 2 Jan. 389/2: [H]e stopped his rush with the utmost sangfroid, and planted one, two, on his upper works .
1842		Whip & Satirist of NY & Brooklyn (NY) 22 Jan. n.p.: Although Crawley one-twoed his man, he caught toco for his pains [...] and was sent to grass.
1844		J.W. Kaye Peregrine Pultuney I 87: In spite of of his weight and his butting he got one-two in that part of the face which lies between the nose and the mouth.
1847		Bell’s Life in Sydney 10 Apr. 2/4: The Australian slipped his one-two heavily on the ribs.
1848		Flash Dict. in Sinks of London Laid Open 118: One two, two blows succeeding each other.
1852		Bell’s Life in Sydney 14 Feb. 1/2: [He] gave him one-two bang in the front of the head.
1853		N.Y. Clipper 4 June 3/1: English was no sooner up to the mark, than he sent his one, two, on Jack’s ribs.
1867		Bell’s Life in Sydney 2 Mar. 5/2: He delivered a rib-bender but received a one-two for his pains.
1882		Nat. Police Gaz. 21 Oct. 11/2: Cribb in a twinkling put in his one-two with [...] punishing severity.
1899		C. Rook Hooligan Nights 69: Let’s give ’im a one two.
1910		L.A. Herald 28 Feb. 6/1: This new series of punches is not one-two at all, but is one-two-three-four-five, being an improvement on the one-two business.
1931		G. Milburn ‘Convicts’ Jargon’ in AS VI:6 440: one, two, n. A kind of blow.
1939		J.L. Dove ‘Fighting Ben’ in Mss. from the Federal Writers’ Project 🌐 A fellow tried to scare my horse while I was on my way to Edgefield. I jumped on him at the courthouse and was giving him the one-two when a friend stopped me.
1943		Courier Mail (Brisbane) 15 Oct. 1/3: [headline] [General] MacArthur Gives the Old ‘One-Two’.
1946		Mezzrow & Wolfe Really the Blues 130: Inspiration’s old lady finally conked me with a one-two.
1951		Sydney Morn. Herald 21 Feb. 12/5: ‘Sugar’ Ray Robinson executes his ‘one-two’ puinch against Jake LaMotta.
1951		Courier Mail (Brisbane) 22 Feb. 9/4: Robsinon [...] executes the old one-two sequence in his middle weight title against Jake La Motta.
1973		Mushy Callahan in Heller In This Corner (1974) 108: So Wayne Morris is supposed to hit him with a one-two and knock him out.

2. in attrib. use of sense 1.

1937

Cairns Post (Qld) 6 Dec. 5/7: Burdett was a better one-two boxer.

3. (US) a speedy exit, a quick departure.

1909		J. Ware Passing Eng. of the Victorian Era 188/2: One-two (Peoples’). Familiar figure of speech for rapidity.
1931		G. Milburn ‘Convicts’ Jargon’ in AS VI:6 440: one, two, n. [...] a quick get-away.
1949		Monteleone Criminal Sl. (rev. edn).

4. a quick survey.

1943

T. Marvin ‘College for Crooks’ in Ten Detective Aces Feb. 🌐 Now, let’s give this place a quick one-two.

5. an act of male masturbation.

1966

Trimble 5000 Adult Sex Words and Phrases 143: one-two (Sl.) Male self Masturbation.