Nice, good and great are words in the American vocabulary used to casually assert approval in a conversation. Awesome! they say when you tie your shoelaces on your own.

Groovy, keen, neat (and neato-keeno) were used in a similar fashion when I was a young kid in the sixties. These slang words evolved into far-out (a John Denver favorite), solid (from The Mod Squad), psychedelic, and others that are fast escaping my memory. Copascetic was popular among an erudite few.

Cool seemed to come in with the beatnik poets of the 1950s, and has survived to the present. Swell was first popular some decades before that, I've read. The elders thought it slightly vulgar and thus the youth used it with enthusiasm. Swell is still heard here and there today, with spot-free acceptance.