society > armed hostility > attack > action or state of siege or blockade > besiege or blockade [verb (transitive)] > undermine (3)
transitive. To undermine.
transitive. To dig or excavate beneath, to make a passage or mine under (a wall, etc.), esp. as a military operation; to sap.
transitive. To dig under the foundations of (a wall, etc.). Also transferred of natural agencies, etc.: To undermine; to render insecure by removing…