(adj) Something so great, or tremendous, and unbelievable that it supersedes all other synonyms of both good and extraordinary.
Although she was nothing more than an iconoclastic misanthrope, she had to admit that her adversary's discovery was radtastic.
by Bradley Darren Davidson November 14, 2006

by Devin Starr May 16, 2009

"That was radtastic"
by Penispenispenis69 March 25, 2020

by asdfcodyjkl; August 14, 2008

Bob: Hey, Guess what cindell, it's friday.
Cindell: AGAIN??? ARE YOU SERIOUS??
Bob: yep.
Cindell: OH MAN, THAT's SO RADTASTIC, I HARDLY KNOW WHAT TO DO WITH MYSELF!!
Cindell: AGAIN??? ARE YOU SERIOUS??
Bob: yep.
Cindell: OH MAN, THAT's SO RADTASTIC, I HARDLY KNOW WHAT TO DO WITH MYSELF!!
by Cindell Corbeil December 20, 2007

Sarah is radtasic.
Ashley, that stunt was so "rad". Radtastic
Tonight is going to be so radtsatic.
Tonight is going to be so rad.
Ashley, that stunt was so "rad". Radtastic
Tonight is going to be so radtsatic.
Tonight is going to be so rad.
by Holly. October 23, 2007

Rad and fantastic combined making a force to be rekoned with. If you are radtastic you are the best.
by sctso April 28, 2003
