Green’s Dictionary of Slang

to set on, to have someone attack a third party, to set someone on another person.

1899		W.J. Kountz Billy Baxter’s Letters 56: When she first came I said to myself, ‘Billy, my boy, here’s your chance; break in and cop out an heiress.’ So I sicked myself on to her.
1906		S. Ford Shorty McCabe 223: Don’t you try to sick any girls on me, or I’ll take to the tall timber.
1907		Crittenden Record (Marion, KY) 19 Dec. 8/6: Get your elbows out o’ my ribs and beat your steamboats out o’ the car or I’ll sic a copper on you!
1910		F.P. Dunne Mr Dooley Says 41: She’d put on her bonnet an’ r-run over an’ sick th’ widow O’Brien on me.
1914		S. Lewis Our Mr Wrenn (1936) 65: Hustle up with that bale, Pete, or we’ll sic Bill on you.
1925		D. Hammett ‘The Scorched Face’ Story Omnibus (1966) 69: I called up the Old man [...] and asked him to sic an operative on Irma Correll’s past.
1935		C.G. Finney Circus of Dr Lao 71: They laughed at the little old man’s frenzy, threatening to sic the Japs on him if he didn’t pipe down.
1940		D. Burley N.Y. Amsterdam News 7 Dec. 20: The boss sicked ’em [i.e. showgirls] on that millionaire.
1953		J. Thompson Criminal (1993) 56: If the Star [...] sicced the d.a. on you, you’d confess.
1960		E. De Roo Big Rumble 34: He’s sicced Scratcher looeys on me.
1963		B. Sorkin Steel Shivs 9: Rami, the guy who had sicked her on him.
1969		‘Iceberg Slim’ Pimp 116: Sic Miss Peaches on him.
1977		A. Brooke Last Toke 131: The management [...] would sic the man on the pimp for the girl everyone had to know had been tricking in order to afford to live there.
1986		S. King It (1987) 304: You better leave me alone or I’ll sic Haystack here on you.
1990		S. Morgan Homeboy 21: Jump state and the feds get sicked on you and those boys don’t know quit.
1992		T. Williams Crackhouse 93: The girls, if they had a problem with another girl, they would sic my daughter on them.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 413: I bought Jack West Virginia and illinois, and he sicced his cocksucking kid brother on us.
2010		L. Redhead Thrill City [ebook] Most likely the same someone who sicked Watto onto me.
2014		R. Hart ‘Confessions of a Taco truck Owner’ in ThugLit July [ebook] It made me wonder if he sicced the health inspector on me, too.
2021		T. Pluck Boy from County Hell 323: The dog handler sicced a wolf mix on a Black inmate dressed in enormous padding.
2021		C. Hammer Opal Country 251: ‘[T]hey’ll think she played them, that she sicked them onto Barret’.