What is Adverse User?

Legal Definition
An adverse user is sack a use of the property as the owner himself would make, asking no permission, and disregarding all other claims to it, so far as they conflict with this use. Blanchard v. Moulton, 63 Me. 434 ; Murray v. Scribner, 74 Wis. 602, 43 N. W. 548; Ward v. Warren, 82 N. Y. 265.
-- Black's Law Dictionary