To counterbalance; to avail against with equal force or virtue; to compensate for, or serve as an equivalent of or substitute for. Countervail livery. At common law, a release was a form of transfer of real estate where some right to it existed in one person but the actual possession was in another; and the possession in such case was said to “countervail livery,” that is, it supplied the place of and rendered unnecessary the open and notorious delivery of possession required in other cases. Miller v. Emans, 19 N. Y. 387. Countervailing: equity. See EQUITY.