1erode the base or foundation of (a rock formation):the flow of water had undermined pillars supporting the roof
dig or excavate beneath (a building or fortification) so as to make it collapse:the demolition engineers did eventually undermine two of the tower’s six sides
2lessen the effectiveness, power, or ability of, especially gradually or insidiously:this could undermine years of hard work
Derivatives
underminer
noun
Origin:
Middle English: from under- + the verb mine2, probably suggested by Middle Dutch ondermineren
undermine in other Oxford dictionaries
Definition of undermine in the US English dictionary
