How Well Do You Know English Slang?
1590s, "profoundly reverential," from awe (n.) + -some (1). Meaning "inspiring awe" is from 1670s; weakened colloquial sense of "impressive, very good" is recorded by 1961 and was in vogue from after c.1980. Related: Awesomely; awesomeness.
Excellent; wonderful; outstanding; cool, neat (Teenagers)
Excellent! Great!: You fixed it? Awesome!