countermine noun 3verb 2forms 3 noun3 •A mine used by defenders to intercept an enemy mine or tunnel.Normally the threat would have been dealt with by means of a counter-mine, but the tunnel was now far too close for that. — 1990 •An underground gallery excavated to intercept and destroy the mining of an enemy. •A stratagem or plot by which another stratagem or project is defeated.Thinking himself contemned, knowing no countermine against contempt but terror. — 1587 verb2 •To plot opposition; to frustrate the initiatives of another.[…] every gamester will agree how necessary it is to know exactly the play of another, in order to countermine him. — 1749 •to sap hostile mining.[…]so Fritz could sleep easily in his trench, so far as mines were concerned; and Fritz, confident in his Herr Professors, altogether neglected any attempt to counter-mine. — 1923 formscountermined · countermining · countermines