Green’s Dictionary of Slang

(US) an intensifier, usu. positive and added to various words, e.g. smackeroonie.

1913		E.L. Warnock ‘Terms of Approbation And Eulogy’ in DN IV:i 25: peacharooney. Something splendid or fine [...] ‘Her hat is just peacharooney’.
1944		Post (Lanarks) 23 Apr. 6/3: Peacharooney — atrtractive.
1947		S.J. Perelman ‘No Dearth of Mirth’ in Keep It Crisp 83: It’s the cat’s pyjamas – a peachamaroot!
1952		(con. 1948) G. Mandel Flee the Angry Strangers 236: Only bad thing is the kids nowadays they ain’t got enough from jiveroony. They get hooked on the real hook.
1955		Mad mag. Aug–Sept 7: Gosharootie! Such a wondrous magazine!
1957		Kerouac On The Road (1972) 166: Slim Gaillard is a tall, thin Negro [...] who’s always saying ‘Right-orooni’ and ‘How ‘bout a little bourbon-orooni’.
1961		H. Ellison Rockabilly (1963) 63: Your boy Stagorooney does a good job.
1962		Mad mag. July 10: Let’s splitarooney before they dig the last gig we pulled.
1970		T. Southern Blue Movie (1974) 47: Angela Sterling [...] nailing, as she did, a cool one and a quarter big ones per pic, plus ten per cent of the boxoroonie.
1972		B. Rodgers Queens’ Vernacular 141: neatarooney (camp) great, wonderful.
1972		R. Barrett Lovomaniacs (1973) 11: So she’s the star of six million smackeroonies worth of picture?
1974		(con. 1945) E. Thompson Tattoo (1977) 346: A special hello and a big smackereenie today for the fighter jockeys at Fürstenfeldbruck.
1979		D. Gram Foxes (1980) 17: ‘Fuckeroon,’ she grumbled.
1979		E. Torres After Hours 7: A hoodlum like Joe Cass [...] a regulation Mafia-ooney!
1986		C. Stroud Close Pursuit (1988) 305: Nunzio is not all that healthy in the old beaneroonie, if you get my drift.
1987		‘Joe Bob Briggs’ Joe Bob Goes to the Drive-In 112: Game over. Big checkarooney goes to Guppy.
1997		N. Barlay Curvy Lovebox 71: Busy schedulerooni na mean.
1997		Bug (Aus.) 1 Oct. 🌐 Super Leek, despite its huge grand final attendance, was a floperoonie in its first year.
2000		C. Cook Robbers (2001) 43: Allrightarooty, okay, what kinda model?
2002		S. Maloney Something Fishy (2006) 101: Sandra saw her and darted forward, smoocheroonie.
2009		R. Milward Ten Storey Love Song 54: [She] spins Bobby onto the floor and gives him a big fat smackeroony.
2023		R. Milward Man-Eating Typewriter 81: [T]he Christians and Colonics were ‘squiffy’ or ‘squifferoony’.