A substitute word or phrase that, while constructed to be socially more acceptable, drastically subtracts from the legitimate intent and purpose of the original.
So, how do we go from 'shell-shock' to 'battle-fatigue', from 'old dude' to 'senior citizen', from 'rape victim' to 'unconsenting intimacy participant'? Because our culture thrives on caustic euphemism: The dumbed-down, homogenized, neutralized language of the mindless majority who want it that way...
A filthy, stinking person who does not believe in using soap and water and becomes hostile when people do not give them money when they are panhandling. The core word, crust, is derived from layers of matter affixed to certain areas of the crusticle's body, which emits a foul odor.
That crusticle just called me a mother****er because I wouldn't give him a dollar.