really cool, but in a more subtle way. as opposed to extreme or awesome. one of the highest compliments you can give someone. being rad is like being cool without having to work for it. it's like a natural coolness.
she seems quiet at frist, but she's actually pretty rad when you get to know her.
these pro skaters have it all wrong, it should be less extreme and more rad, like it was back in the day.
Several definitions given here are correct in connecting the term to radical but incorrect in the date of origin. Being old enough, I can attest that it was used at least as far back as the seventies.
"The NinjaTurtles never invented a single term. To suggest so is not rad but very uncool."