Interesting article* by David Skinner about how ‘cool’ became one of the main words in the counterculture signifying approval. It started out earlier than I’d imagined – in the 1930s – gaining traction in the 1950s and 1960s, mostly in those days associated with jazz, but swiftly broadening both its meaning and its usage.
The question not addressed by the writer is why, among a whole slew of slang words from that era – hip, hep, groovy, square and so on – it should remain such a doughty survivor over half a century later. Most of those other ones are now uncool and can only be used with at least a hint of irony.
*David Skinner, ‘How did cool become such a big deal?’, Humanities, http://www.neh.gov/humanities/2014/julyaugust/feature/how-did-cool-become-such-big-deal-0