They started in Bohemia as the gypsies of Eastern Europe. By 1910, they were synonymous with those who didn't fit in — like the non-conforming, scandalously immoral artists of Greenwich Village. Not without redeeming value, Bohemians were in some quarters considered hep (1903), "informed" or "knowledgeable."
Hep slipped into hip (1931), jazzmen making for hip cats dating cool chicks. Those "in the know" were definitely hip.
Hip extended itself during 1945-55 with the emergence of the hipsters who in turn spawned the Beat generation (1957). Ginsberg and Kerouac were its prime exemplars. Its foundlings were beatniks — one of the many -ik words spun off the launch of the Soviet Sputnik (a "traveling companion.").
Serious beats begot the anti-establishment brats known as hippies and rebels without a cause, from the title of Robert Lindner's book (1954) and the popular James Dean movie (1955).
Tie-dyed, adorned with love beads, sandals, and granny glasses, they founded the Woodstock Nation on August 15, 1969 at 7:00 A.M. on a dairy pasture in upper New York state. In '68 came the Yippies, the Youth International Party of Rubin and Hoffman, transmogrifying into today's Yuppies — truly the children our parents warned us against.