Green’s Dictionary of Slang

a mentally unstable person, with overtones of sexual perversion.

1963		in T.I. Rubin Sweet Daddy 137: Be funny – no more around all the sickoes.
1976		R. Price Blood Brothers 240: Check out the sickos who come in here.
1981		J. Sullivan ‘The Russians are Coming’ Only Fools and Horses [TV script] You sicko!
1986		H.B. Gilmour Pretty in Pink 12: Kate hissed, ‘You sicko!’.
1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Sicko. A prisoner regarded as deviant by his peers, usually because of his preoccupation with sex.
1998		I. Welsh Filth 322: She was going through a pretty hard time with this sicko hassling her.
1999		Indep. on Sun. Rev. 1 Aug. 8: A ‘sicko’ has to be involved.
2000		Sun. Times Mag. 6 Feb. 23: There’s always been sickos riding the rails.
2001		N. Green Shooting Dr. Jack (2002) 189: This guy was the kind of sicko that would be fun.
2005		E. White My Lives 233: Paid performers in a scenario dreamed up by the tubby sicko over there.
2005		H. Mantel Beyond Black 125: Then they lolled their tongues out and retched, because they confused a perv with a sicko.
2009		P. Temple Truth 309: You couldn’t carry on in the job if your daughter accused you of sexual abuse. [...] You were a sicko, you were a disgusting pervert.
2010		IOL News (western Cape) 20 Jan. 🌐 Lovelot, 33, is determined to find the sicko who tortures innocent animals.
2011		S. Seamans ‘Creation of Ice’ in Pulp Ink [ebook] There’s a lot of sickos out there willing to pay big money for a tight young piece of ass.
2019		S.M. Jones Lives Laid Away [ebook] ‘You’re the monstrosity that cut a distribution deal with a few rogue ICE units, right? The sicko who bought up Duke Ducane’s trafficking routes?’.
2021		J. Ellroy Widespread Panic 193: The six sickos slide and slither inside.
2021		L. McInerney Rules of Revelation 145: ‘Jesus. What kind of songs are you sickos writing?’.