Green’s Dictionary of Slang

pinko n.

also pinkie
[pink adj. (2) + -o sfx (2)]

(orig. US) a communist, socialist or even mildly liberal sympathizer (depending on the speaker’s viewpoint).

J.G. Cozzens Men and Brethren 104: She’s a good girl [...] Now only a healthy pinko. I’ve snatched her like a brand from the Young Communist League burning.
‘B. Rose’ Wine, Women and Words 105: I wouldn’t call him a Commie, but if he doesn’t get a check from Moscow every week, he’s being robbed [...] Unfortunately the pinko didn’t drinko.
[US]H.S. Thompson letter 12 June in Proud Highway (1997) 170: Hoarse shouts of ‘kill them pinkos!’ from a black-shirted band of Legionnaires.
[US]J. Crumley One to Count Cadence (1987) 227: You sit down in Mickey’s with those damned pinkos.
[US]E. Torres Q&A 135: Bunch of fuckin’ pinkos.
[Aus] in J. Miller Koori 218: Since I believe in Koori land rights and no dams on the Franklin River, that makes me a black, greenie, pinko.
[Aus]B. Moore Lex. of Cadet Lang. 269: pinko someone perceived as being a communist sympathiser, or some sort of ‘commo’ in his attitudes.
[US]T. Udo Vatican Bloodbath 112: Maybe his real enemies hadn’t been the Catholics and the homosexuals, the pinkos and the reds.
[Aus]Macquarie Dict. [Internet] pinko noun 1. Also, pinkie. a Communist or Leftist sympathiser.
[Aus]P. Temple Broken Shore (2007) [ebook] What do you think this Fyfe jackal is slinging the pinkos?