Available Definitions:
1) n. - An underground gallery excavated to intercept and destroy the mining of an enemy.
2) n. - A stratagem or plot by which another sratagem or project is defeated.
3) v. t. - To oppose by means of a countermine; to intercept with a countermine.
4) v. t. - To frustrate or counteract by secret measures.
5) v. i. - To make a countermine or counterplot; to plot secretly.