Green’s Dictionary of Slang

1. (orig. US) to rob or otherwise influence someone through threats and potential, rather than actual, violence.

1903		Monthly Maroon June 444: If he refused, Phil, who would be near by, was to strong-arm him while Tommy took away the badge [DA].
1927		(con. 1917) J. Stevens Mattock 83: I saw he was ready to leap, and I strong-armed him. ‘What the hell do you know about Lardner?’ I says.
1934		Times (Hammind, IN) 6 Jan. 10/2: She was walking on 19th ave and [...] they ‘strongarmed’ her and took her purse.
1945		J. Fishman Bullets for Two 7: [He] had been arrested on a charge of strong-arming a defaulting client and both members of the firm had spent four months in jail.
1953		‘William Lee’ Junkie (1966) 79: They usually have money. When they don’t, they expect credit. If you refuse, they will try to strong-arm you.
1960		C. Cooper Jr Syndicate (1998) 83: The bulls strong-armed me up to Markle’s office.
1962		Ragen & Finston World’s Toughest Prison 820: strong arm – An assault – to beat; to rob by violence.
1973		E. Bunker No Beast So Fierce 131: When I was fifteen, I’d strong-armed an elderly Chinese.
1985		N. Pileggi Wiseguy (2001) 101: I just strong-armed them out of the money.
1999		G. Seal Lingo 50: Contacts with the USA have given us [...] strong-arm, to physically intimidate; and probably heat, meaning pressure from the authorities.
2005		J. Stahl I, Fatty 199: Brady would have probably strong-armed them like he did all the other witnesses.
2010		A. Steinberg Running the Books 165: He’d strong-amed Miller into throwing out the weapon.
2015		J.W. Davidson (con. 1740s) Little History of US 90: [Captain] Cheap relied on the midshipman Alexander Campbell to strong-arm the crew and enforce his orders.

2. (US Und.) to carry out a form of robbery whereby a woman, posing as a whore, lures a man into a dark alleyway or similar space; she then puts a stranglehold around his neck and her male partner(s) rob(s) the victim, who is thus held captive.

1937

‘Boxcar Bertha’ Sister of the Road (1975) 307: The robber, in strong-arming a victim grips the victim’s neck and chokes him. As she is doing that, she has at least one accomplice — usually two — who go through the pockets of the victim and punch him in the abdomen or in the head and knock him down and run.