Definition of undermine in US English:



[with object]
  • 1Erode the base or foundation of (a rock formation).

    • ‘The lighthouse stands on a plinth of rock undermined by caves, perhaps once used by smugglers.’
    erode, wear away, eat away at, chip away, undercut
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    1. 1.1 Dig or excavate beneath (a building or fortification) so as to make it collapse.
      • ‘The disaster was caused by the total collapse of his house in the Rue d' Anjou, undermined by the excavations carried out by the bank next door for its strong room.’
      • ‘The Romans also developed tunnelling for military purposes, either by breaking through behind enemy defences or by undermining fortifications to cause their collapse.’
      • ‘Within days, the French advanced into the city outskirts and undermined numerous buildings.’
      tunnel under, dig under, burrow under, excavate, sap
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  • 2Damage or weaken (someone or something), especially gradually or insidiously.

    ‘this could undermine years of hard work’
    • ‘What they don't understand is that being boring limits their power and undermines their effectiveness.’
    • ‘That law undermined the power of local authorities.’
    • ‘Mistakes or excessive collateral damage can undermine its potential effectiveness.’
    • ‘It also undermines their ability their ability to trade in the peak Christmas season.’
    • ‘Their mental impairments may have also seriously undermined their ability to assist in their legal defense.’
    • ‘Damage to the brain's left side often undermines language abilities.’
    • ‘They might have to share power and that is dangerous because it would undermine their position of power.’
    • ‘That undermined the hard power strategy of the country in a very concrete way.’
    • ‘And so, while she was demanding great things of us, she was also, in a way, undermining our ability to fulfill them.’
    • ‘Our central argument with the producers is that their ‘new’ work practices are undermining our ability to do our trade.’
    • ‘And yet, the way he handled the events that followed gradually undermined his position.’
    • ‘Abusing the student programs in this way not only undermines the power of the union, but students are also being asked to do jobs for which they are not trained, raising concerns about health and safety.’
    • ‘I think all this niceness undermines our power.’
    • ‘This compromise has clearly undermined the church's ability to present the gospel with power and authority.’
    • ‘And it is this influence which is understandably resented by many, who see it as insidiously undermining our own culture.’
    • ‘Nation states will not be interested in enabling that power, only in undermining it.’
    • ‘Those who undersleep are undermining their cognitive abilities - whether meagre or not - as well as their private life and health.’
    • ‘Many in positions of power undermine others and the organization to meet their own selfish needs.’
    • ‘Foreign debt undermines the country's ability to act independently.’
    • ‘It undermines their ability to do their job and sets a bad example to the rest of the company.’
    subvert, sabotage, threaten, weaken, compromise, diminish, reduce, impair, mar, spoil, ruin, impede, hinder, damage, hurt, injure, cripple, disable, enfeeble, sap, shake
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Middle English: from under- + the verb mine, probably suggested by Middle Dutch ondermineren.