undermine

To weaken by wearing away a base or foundation.

To weaken, injure, or impair, often by degrees or imperceptibly; sap.

To dig a mine or tunnel beneath.

To form a mine under; sap; render unstable by digging or wearing away the foundation of; make an excavation beneath, especially for the purpose of causing to fall, or of blowing up: as, to undermine a wall; a river undermines its banks.

Figuratively, to subvert by removing clandestinely the foundation of; injure by invisible, secret, or dishonorable means.

To injure, weaken, or destroy insidiously or indirectly; wear away; wear out; sap.

Same as mine, 2 .

A cave.

To excavate the earth beneath, or the part of, especially for the purpose of causing to fall or be overthrown; to form a mine under; to sap.

Fig.: To remove the foundation or support of by clandestine means; to ruin in an underhand way.