erratic: Meaning and Definition of

er•rat•ic

1. deviating from the usual or proper course in conduct or opinion; eccentric; queer: erratic behavior.
2. having no certain or definite course; wandering; not fixed: erratic winds.
3. noting or pertaining to a boulder or the like carried by glacial ice and deposited some distance from its place of origin.
4. (of a lichen) having no attachment to the surface on which it grows.

1. an erratic or eccentric person.
2. an erratic boulder or the like.