Green’s Dictionary of Slang

pinko adj.²

left-wing.

1925		Time 29 June n.p.: The gulf that yawns today between Wall Street and Vesey Street, where the now pinko Nation is published, was narrower in those days.
1944		N. Mitchison Among You Taking Notes 2–5 Oct. 296: It seems rather pinko and Liberal and full of good resolutions.
1959		C. MacInnes Absolute Beginners 38: Your pinko pals did what they wanted to when they got power.
1966		H.S. Thompson Hell’s Angels (1967) 269: If Sonny had a beef with some pinko demonstrators, then by God, they all had a beef.
1973		B.S. Johnson All Bull 253: I don’t remember ever having heard of the UN at Eton: if I had it would have been only as a pinko joke.
1987		‘Joe Bob Briggs’ Joe Bob Goes to the Drive-In 102: He’s generally fed up with all the pinko liberal cop-haters and bureaucrats.
1999		Guardian Saturday Rev. 26 June 11: Any lily-livered Groucho Club pinko Brit.
2000		Indep. Rev. 25 Apr. 8: We condemn the defamatory and libellous statements calling Bishop Fred Henry [...] a ‘pinko commie’.
2019		D. Winslow Border [ebook] [A] lesson they won’t learn at university from the pinko professors who coddle the little darlings.
2024		J. Meades Empty Wigs (t/s) 151: [T]he Garrick [...] Not one of my usual haunts, I hasten to add. A jot pinko for my taste.