I'm not sure what you mean by the definition of badass, but songs that got me hype and some even ready to rumble:
(Nothing works quite the same as gangsta rap; though let me add that I find a lot of the language and imagery, especially pertaining to African Americans in gangsta rap objectionable, I still enjoyed these hardcore songs)
Never Scared-Bonecrusher
Ain't No Play in GA-Pastor Troy
Vice Versa-Pastor Troy
What Up Gangsta-50 Cent
Hit 'Em Up-Tupac
Tradin War Stories-Tupac
Hail Mary-Tupac
Bury Me a G-Tupac
Notorious Thugs-Notorious BIG feat. Bone, Thugs, N Harmony
Down Bottom-Ruff Ryders
What's My Name?-DMX
M.C. Hammer-Rick Ross
Quiet Storm-Mobb Deep feat. Lil' Kim
Wild Out-The Lox
Deep Cover-Dr. Dre and Snoop Dogg
Bout It Bout It-Master P
Tear the Club Up-Triple Six Mafia
No Vaseline-Ice Cube
Gangsta, Gangsta-NWA
Straight Outta Compton-NWA
Boyz in the Hood-Eazy E
Bawitdaba-Kid Rock
I'm Bad-LL Cool J
King of Rock-Run DMC
Playaz Circle-Duffle Bag Boy
Thuggish Ruggish Bone-Bone, Thugs, N Harmony
Others:
Welcome to the Jungle-Guns N' Roses
Blaze of Glory-Bon Jovi