A badass is a man (or bear) that can perform seemingly impossible feats of strength...while sleeping.
A badass is defined as someone who can "kill a bear, an army of Viet Cong, and an evil business tycoon, all in one swift, but deadly, move." Badasses are generally capable of eating someone's soul, while leaving an empty shell behind. Badasses are people who are worshipped as Gods by society.
Various feats accomplished by badasses: Blowing up the Death Star. Going back in time and killing Hitler. Crushing the USSR in a game of monopoly. Being responsible for 99% of deaths world-wide.
A total list of all living non-fictional badasses: Chuck Norris, Steven Seagal, Harrison Ford, Bruce Lee, Mewtwo, Chewbacca, King Leonidas, Raptor Jesus, Optimus Prime, BATMAN, me, my dad, Pirates of the Caribbean: Curse of the Black Pearl, Metallica, Jack Bauer, Manbearpig, Michael Phelps, Christopher Walken, Gary Sinise, Samuel L. Jackson, Wolverine, and Nightcrawler
Anti-badasses (people who suck the badassness out of every room they enter): Al Gore, Meg Griffin, David Caruso, Tobacco, old people, people who care about the Greek myths not dealing with war or boning, Michael Cera in every non-Superbad movie.
As you can see, badasses are cool and could kick your ass in 1 second.