1. An erection of the penis...
2. What happens to a girl's nipples when she gets cold or has water poured on her tits (like in a wet t-shirt contest)
3. A description of sex
1. "I stay hard throughout my Spanish class cause my teacher's so damn hot."
2. "My nipples are getting hard..."
3. "If you finger me good, I'll do you really hard."
Tough, mostly because of poverty and surviving (or not) public schools. Something to be said of poor, urban American youth and essentially no one else. Marked by resourcefulness, pragmaticism, and coldness. As a result of being shit on one too many times. A desirable trait. Can also be the result of an awful family life/childhood. See also hardcore
