Undermine

Part of speech: verb (v.)

1. 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; as, to undermine a wall. A vast rock undermined from one end to the other, and a highway running through it. Addison.

2. Fig.: To remove the foundation or support of by clandestine means; to ruin in an underhand way; as, to undermine reputation; to undermine the constitution of the state. He should be warned who are like to undermine him. Locke.