1. past tense of countermine; to dig a tunnel or mine to intercept or destroy an enemy’s mine
Usage: military; historical
2. past tense of countermine; to work against or thwart someone’s plans or schemes
Usage: figurative

Examples

• The defenders countermined the enemy’s tunneling efforts beneath the fortress walls.
• Engineers countermined the siege works to prevent the castle from being breached.
• She countermined his political ambitions by exposing his corruption.
• The rival company countermined their expansion plans through strategic acquisitions.
• Military sappers countermined the attacking force’s underground approach.
• His opponents countermined every proposal he made in the committee.