Green’s Dictionary of Slang

-o sfx

1. used variously to create extended nouns, often as terms of address, e.g. boyo n. (1); bucko n.1 (2); kiddo n. (1)

[UK]Shakespeare Romeo and Juliet II iv: The pox of such antick, lisping, affecting fantasticoes, these new tuners of accents!
[UK] ‘Chipps of the Old Block’ in Rump Poems and Songs (1662) ii 18: Salloway with Tobacco, / Inspired, turn’d State Quacko.
[US]J.T. Farrell World I Never Made 86: Nix, nix on that stuff! [...] Nix on the slango.
[US]T. Thursday ‘Good Luck is No Good’ in Federal Agent Nov. [Internet] Listen, punko, you don’t know what luck is!
[US]W. Winchell On Broadway 25 Oct. [synd. col.] Exhibitors have revived Universal’s floppo ‘Gift of Gab’.
[UK]R. Llewellyn None But the Lonely Heart 254: Rossi was such a quiet, posh sort of a bloke, even if he did talk ice creamo.
[US]T. Thursday ‘Twin Lose or Draw’ in Popular Sports Spring [Internet] He was known as a club fighter, i.e., a sucker sappo—crowd-pleaser.
[US]Kramer & Karr Teen-Age Gangs 189: Look, punko, you’re big and brave with the kids. But this girl likes men.
[US]T. Williams Camino Real Block Seven: Hold the lady’s chair, cretino!
[US]B. Appel Sweet Money Girl 43: You act like your cripples have b.o. and every other kind of stinko.
[US](con. 1950) E. Frankel Band of Brothers 14: Whew! You stink, friendo!
[US]L.F. Cooley Run For Home (1959) 109: It’s better to let them think you’ve got five balls than to let ’em think you’re a ‘queer-o’.
[UK]J.P. Carstairs Concrete Kimono 150: Don’t give me those big innocent eyes. Strictly for the birds—the old spinacho! In other words, Alfafa!
[US]L. Bruce Essential Lenny Bruce 77: Would that be a twist-o.
[US](con. late 1940s) E. Thompson Tattoo (1977) 484: He’s a freak-o all right.
[US]H. Ellison ‘Neon’ in Deathbird Stories (1978) 91: Get offa there, you freako-pervo-devo!
[US]J. Ellroy Brown’s Requiem 190: For treating me like a slave! Like a retardo!

2. used variously to create nouns from adjs., e.g. pinko n.; weirdo n., wido n.

[US] in Journal of Amer. Folklore Apr. IX 32: De book say, dat white-o, brown-o, black-o, all mek de same blood.
[US]W. Winchell On Broadway 30 Sept. [synd. col.] ‘Fargo’ (the reviewers mourned) is a dullo.
[US](con. late 1940s) E. Thompson Tattoo (1977) 571: Oh, like maybe our parents aren’t such stupid-os after all.
[UK]H.B. Gilmour Pretty in Pink 116: Give Mr. Perfecto a squeeze for me.
[US]J. Stahl Plainclothes Naked (2002) 184: What sort of strange-o would want a porky redhead as a pinup.
[US]J. Stahl I, Fatty 22: Geeks and deform-os.
[UK]Guardian G2 4 Sept. 3: Freeing the piano for a true keeno.

3. (mainly Aus.) added to a variety of nouns (often occupational) to create sl. forms, usu. abbreviated, e.g. arvo n.; bombo n.1 ; commo n.; compo n.; dero n.; ethno n.; garbo n.; jollo n.; journo n.; lezo n.; maddo n.; Metho n.; milko n.; nasho n.; plonko n.; rabbit-o n.; reffo n.; sano n.; secko n.; sheepo n.; susso n.; sypho n. [? f. the -o sfx in street cries such as milko! or in the familiarization of names, e.g. Johno].

[Aus]A. Weller Day of the Dog 9: We never come to see ya in jail because Freo drives us crazy.
[Aus]J. Davis Dreamers 83: Freeo? What’s wrong with Fremantle Gaol?

4. (mainly Aus.) less commonly added to adjs. to create shortened sl. forms, e.g. berko adj.; troppo adj.

[Aus]R. McDonald Rough Wallaby 15: ‘Beaut-o,’ gasped Terry.

5. used variously to create extended adjs., e.g. cheapo adj., neato adj.

[US]Van Loan ‘The National Commission Decides’ in Score by Innings (2004) 298: ‘Well, all work and no play makes jack a dull boy, you know.’ ‘Correct-o!’ said Whelan.
[US]F. Kohner Gidget Goes Hawaiian 48: He looked like the cleanest guy going and his physique was keeno.
[US]P. Thomas Down These Mean Streets (1970) 5: The bad-o feeling came back. About Poppa not knowing I’d cut out from home, and Momma worrying ’cause she knew. That wasn’t fair at all.
[US]E. Bogosian Talk Radio (1989) 65: You’re a hoax. You call me with some fake-o story.
[US]‘Joe Bob Briggs’ Joe Bob Goes to the Drive-In 201: A bunch of weird, stripped down, California flake-o off-road vehicles.
[US]C. Hiaasen Stormy Weather 260: Boy, this weather’s suck-o.
[US]J. Stahl Plainclothes Naked (2002) 60: Carmella was so stunned by his disturbo grin she forgot to hit him again. [Ibid.] 123: Merch [...] ka-banged the defecto candy machine and dug out a Chunky.
[US]J. Stahl OG Dad xiii: If I have any goal [...] it’s not to pass that depresso-bent along to my offspring.

6. used variously to create general shortened forms, mostly of nouns, e.g. aggro n.; ammo n.; combo n.2

7. used as a meaningless ending, e.g. billy-o n.; SE cheerio.

[Aus]W.A. Sun. Times (Perth) 2 Jan. 3/5: Christmas has come and gone, and the boys are all readying up for a ‘ditto repeato’ New Year.
[Aus]C.J. Dennis ‘To the Boys Who Took the Count’ in Moods of Ginger Mick 104: Fer there’s nothin’ like scrappin’ to bare a man’s soul, / If it’s Billo, or Percy, or Gus.
[US](con. 1914–18) L. Nason Three Lights from a Match 159: Let’s get the hell out of here before another [bombshell] sockoes down.
[US]A. Zugsmith Beat Generation 32: What’s cooking, Father-O?
[US]E. De Roo Big Rumble 23: Come on, Larry-O or I’ll lock you up here.
[UK]A. Payne ‘Senior Citizen Caine’ Minder [TV script] 9: You think those labels are going to leap up and plonk themselves on those bottles all on their ownio?