Green’s Dictionary of Slang

(US campus) ridiculous.

1917		Wodehouse et al. Oh Boy! [musical] Don’t be ridic. Come and join the party and be a little ray of sunshine.
1920		A. Baer Speeches of Fuller Durham 8 Aug. [synd. col.] (HEY, REDIC IF YOU GOTTA GIVE US NEWS READ THE ALMANAC) Fuller didn’t know that redic was short for ridiculous.
1929		H.C. Witwer Yes Man’s Land 7: Don’t be ridic!
1938		W. Winchell On Broadway 25 Oct. [synd. col.] Garbo is hiding out at 101 West 55th Street, the reports on the coast that she’s been out there being ridic.
1944		A. Kapelner Lonely Boy Blues (1965) 24: My good man, Don’t be ridic!
1956		J. Curtis Look Long Upon a Monkey 215: Don’t be ridic, my dear.
1989		R.G. Barrett Boys from Binjiwunyawunya 173: Mick always said you were tight with a quid, Les. But mate. This is ridic.
1989		P. Munro Sl. U.
1992		D. Burke Street Talk 2.
1992		R.G. Barrett Davo’s Little Something 5: Len, you’r gonna have to turn the room down. This is ridic.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] ‘What do I have to [...] Nothing too ridic?
2012		(con. 1980s) I. Welsh Skagboys 31: How fuckin ridic is that?
2022		D. Astle on Twitter 3 Aug. 🌐 Social media’s influence on English be ridic af.