If you mean the slang usage of cool, meaning good or interesting or "with it," it became common with the mainstreaming of jazz and particularly the beatnik movement of the 1940s and '50s.
etymologist(Not to be confused with a philologist, one who studies historical literature.)
Beatnik Records was created in 1998.
Mi amigo/a beatnik/bohemio/a
beatnik
Beatnik Girls - 2009 SUSPENDED was released on: USA: 2009
Pleasant Dreams - Beatnik Termites album - was created in 1997.
I Was a Teenage Beatnik - 2005 was released on: USA: 28 August 2005 (limited)
The cast of Van Gore - 2011 includes: Garfield Andrews as Van Gore Clare Blackwood as Beatnik Girl Milan Carmona as Teen Killed Zac Che as Beatnik Imogen Grace as Beatnik Keith Hodder as Narrator Mervyn Joseph as Bad-ass Cop Lise Moule as Art Collector Ellen Tkachenko as Sexy Beatnik
The cast of Pin Wheel - 2007 includes: Court Dickert as Beatnik Cesare Dominque as Beatnik Jaime Engelhardt as Student Julian Flamant as Mason Andrew Fortinberry as Spencer Sheryle Gillette as Sheryle Richard Malave as Beatnik Cydne Mayberry as Student Dennis McLain as Parker Susan Neal as Beatnik Britany Simmons as Britany
Suffix Addiction.
Generally, clothes.
Koko Meets Barney Beatnik - 1963 TV was released on: USA: 13 June 1963
Insight - 1960 Diary of a Beatnik 1-6 was released on: USA: 30 October 1960