Countermine \Coun`ter*mine"\ (koun`t[~e]r*m[imac]n"), v. t. [Cf. F. contreminer.] [imp. & p. p. {Countermined}; p. pr. & vb. n. {Countermining}.] 1. (Mil.) To oppose by means of a countermine; to intercept with a countermine. 2. To frustrate or counteract by secret measures.