Green’s Dictionary of Slang

oddball n.

[SE odd + -ball sfx]

(orig. US) an eccentric, unusual person.

[US](con. WWII) ‘Kriegie Talk’ AS XXIII 221: Odd ball [...] connoted that a prisoner’s strangeness was not the result of prison camp experiences.
[US]H. Gold Man Who Was Not With It (1965) 14: All us complacent oddballs.
[US]N. von Hoffman We are the People Our Parents Warned Us Against 178: A miscellany of street commandos, petty dealers and uncatagorizable oddballs.
[US]Hall & Adelman Gentleman of Leisure 92: I’m the only oddball. I just don’t want to be a robot.
[Aus]M. Bail Holden’s Performance (1989) 281: And you’re quite an oddball. You know that? You’re attracted to cripples and power-maniacs.
[Can](con. 1920s) O.D. Brooks Legs 230: He was as queer as a four-dollar bill, but that didn’t bother me. I’d had three years’ experience dealing with fruits and oddballs.
[Ire]P. Howard PS, I Scored the Bridesmaids 130: Oh, so suddenly I’m the focking oddball?
[US]A. Steinberg Running the Books 74: Hippies covered in dog hair, smiling evangelicals, and local oddballs.