1. a self-obsessed, materialistic person
2. dry and flaky
3. a personality that revolves around physical appearance and shallowness

The gross, white, puss looking crust which forms after a recent piercing. Although you desperately want to pick them off, they do indeed help your piercing heal faster.

Vile spawn of Hippies and Punks, these creatures are so-called because their personal habits include not washing until there is a thick crust of dirt all over them. Often seen sporting crusted dreadlocks as well, and when their itching heads get too much, shaved heads. Must-have accessories for any self-respecting crusty: a dog on a string, army boots, stinking patchouli oil, constant odour of garlic.
Crusties are rabid supporters of political correctness- everyone is equal in their eyes, except of course anyone who does not believe in being a vegan, animal-liberating, tax-dodging punk rocker- everyone else is scum! Crusties tend to congregate at summer rock festivals, camping out and eating vegan slop. The rest of the year, they will travel around in delapidated buses and vans trying to find a place to camp and constantly getting kicked off the land wherever they settle like a swarm of festering dung flies.
Nearly all Crusties are rich middle class kids who think it's cool not to wash for a few years and kill their brain cells with too much acid. Then when it all gets too much, they can go home to Mummy and Daddy and clean up their act and get a job as a social worker or teacher.

A situation, person or action that is delightfully tacky, yet surprisingly refined and enjoyable.

One who resides in the state of Pennsylvania and smokes a lot of marijuana.

it can also be used as a verb "getting crusty"

This word can basically mean any adjective, but in most cases, it will either mean gross, old, and/or ugly (see grody). It can also mean, however, cool or tight.

the feeling the morning after a long night of heavy drinking
being dehydrated and hungover
the general feeling of crust