The first measure of a motherfuckers hardness in the street is their ability to rock, how much punishment they can dole out and how much they can take.
Second is how far a motherfucker is prepared to go as a means to an end, what are you prepared to do to achieve your goals.
Don't do the crime if you can't do the time.
The streets can produce some hardass motherfuckers but the hardest dudes I know are military, they're the ones getting shot repeatedly, blown up, riddled with shrapnel and still, still,..carry five of their wounded buddies back to the LZ for evac.
That's heart and it doesn't get more real than advancing in the face of death.