countermined

Verb

countermine (third-person singular simple present countermines, present participle countermining, simple past and past participle 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. (intransitive, transitive) 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, Frank Fox, “The Man-Made Earthquake”, in Charles Francis Horne, The Great Events of the Great War, volume 5

See all 5 meanings of countermine