Green’s Dictionary of Slang

1. phencyclidine.

1972		Smith & Gay Heroin in Perspective 197: Angel Dust [...] in pill form called ‘Peace Pill’.
1981		D.E. Miller Bk of Jargon 338: peace pills: PCP.
2003		Microgram Bulletin XXXVI:8 183: The acronym PCP is believed to have been derived from the phrase ‘Peace Pills’ (PeaCe Pills).

2. a mixture of LSD and Methedrine.

1971		E.E. Landy Underground Dict. (1972).
1982		AS LVII:4 289: When LSD is mixed with other drugs [...] [s]uch mixtures are today called [...] peace pills.

(US drugs) LSD.

1971		E.E. Landy Underground Dict. (1972).
2001		ONDCP Street Terms 16: Peace tablets — LSD.

(drugs) phencyclidine.

1971		J.H. Frykman A New Connection in Spears (1986).
2001		ONDCP Street Terms 16: Peace weed — PCP.

1. (also peacemake) the penis (cf. matrimonial peacemaker n.).

1665		Head Eng. Rogue Pt I ii 109: [His] Peacemake in amorous dalliances wrought not those effects in me as usually it doth.
1693		T. Brown Salamanca Wedding 4: [...] in case he offends after that manner, full leave to make her self amends before, as she pleases; as also upon a second Trespass, to burn his Peacemaker.
1733		Laugh and Be Fat 27: He had more Wit in his Anger, than to revenge himself of an ill Tongue, by burning his Peace-maker.
1890–1904		Farmer & Henley Sl. and Its Analogues.

2. (US) a pistol or revolver, esp. the Colt .45.

1862		J.R. Lowell Biglow Papers 2nd series (1880) 13: A feller [...] Lep up an’ drawed his peacemaker.
1869		‘South-Western Sl.’ in Overland Monthly (CA) Aug. 126: Among the names of revolvers I remember the following: Meat in the Pot, Blue Lightning, Peacemaker, Mr. Speaker, Black-eyed Susan, Pill-box, My Unconverted Friend.
1873		Knoxville Wkly Chron. (TN) 16 Apr. 1/2: The Rural New Yorker notices the Taylor gun as a ‘peace-making gun’.
1881		Princeton Union (MN) 24 Feb. 5/5: He styles his improved guns ‘Peacemakers.‘ for [...] they will make war entirely out of the question.
1896		Salt Lake Herald (UT) 24 July 7/5: [...] for the purpose of conducting a test of the famous ‘peacemaker’ gun [...] manufactured by the Colt company.
[1913		(ref. to 1844) Sun (NY) 7 Dec. 37/1: Commodore Stockton’s great gun [i.e. of an ironclad vessel], called the Peacemaker, burst and slew two emmbers of the Cabinet].
1934		(con. 1870s) E. Cunningham Triggernometry (1957) 55: I’ll buy Old Peacemaker, here, from Rufe.
1936		R.F. Adams Cowboy Lingo 166: In 1870 the most famous of all ‘six-guns’ made its appearance; the Colt ‘Single-Action Army,’ variously named ‘Peacemaker,’ and ‘Hog leg’.
1969		(con. 1877) J.G. Rosa Gunfighter 58: Hardin saw Armstrong’s 7½-inch-barrel Peacemaker, called out, ‘Texas, by God!’ and reached for his own gun.
1971		N. Smith Gumshoe (1998) 118: I could feel my palms sweating against the stock of the gun. I didn’t relish holding two men with the peacemaker.
1983		R. Klein Jailhouse Jargon and Street Sl. [unpub. ms.].

3. (US und.) a club, a bludgeon.

2021

S.A. Crosby Razorblade Tears 224: [A]n old wooden baseball bat with nails driven into it [...] This peacemaker seemed like a good alternative [to a gun].

4. (W.I.) a male lover.

1954

cited in Cassidy & LePage Dict. Jam. Eng. (1980).

5. (W.I., also peaceman) a police officer.

1956

cited in Cassidy & LePage Dict. Jam. Eng. (1980).

(US black) to be at peace, put at ease.

1996

W.D. Myers Slam! 76: You sitting in the back of a car with your homeboy and maybe some babes and things just peace out for you.