Derived from the root word Crust meaning: rude.
A young person who does not live in a way that society considers normal, typically w/ untidy or dirty clothes and hair, and no regular job or permanent home; Bohemian, Nomadic.
Originally coined "Stenchcore" this extreme 80's evolved subgenre of poltical punk & metal was pioneered by bands like Amebix, Deviated Instinct, & Doom.
Crusties are instinctively anti-authority with varying politically nihilistic values such as anti-work, anti-government, anti-war, anti-religion, anti-vivisection, anti-civilization, etc.
Crusties are also highly individualistic and crudely sophisticated- often self-taught in the D.I.Y. ethos of punkdom, and inclined to travel, trainhop, spange, squat, & dumpster dive as a lifeway; a way of life.
I heard about these two crustie kids who were harassed by a cop, so they kicked him in the nards and tried to sell his utility belt & gun for $5.