countermine

plural countermines

1. 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, Peter Hopkirk, The Great Game, Folio Society, published 2010, page 436

2. An underground gallery excavated to intercept and destroy the mining of an enemy.
3. A stratagem or plot by which another stratagem or project is defeated.

   Thinking himself contemned, knowing no countermine against contempt but terror.

   The New Arcadia

   a. 1587, Philippe Sidnei [i.e., Philip Sidney], “(please specify the folio)”, in [Fulke Greville; Matthew Gwinne; John Florio], editors, The Countesse of Pembrokes Arcadia [The New Arcadia], London: […] [John Windet] for William Ponsonbie, published 1590, →OCLC

present singular third person countermines · participle present countermining · participle past countermined · past countermined

1. 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, Henry Fielding, chapter III, in The History of Tom Jones, a Foundling, volume (please specify |volume=I to VI), London: A[ndrew] Millar, […], →OCLC, book VI

   Synonyms: counterplot

2. intransitivetransitiveto 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, Frank Fox, “The Man-Made Earthquake”, in Charles Francis Horne, The Great Events of the Great War, volume 5