verb (used with object), undermined, undermining.
- to injure or destroy by insidious activity or imperceptible stages, sometimes tending toward a sudden dramatic effect.
- to attack by indirect, secret, or underhand means; attempt to subvert by stealth.
- to make an excavation under; dig or tunnel beneath, as a military stronghold.
- to weaken or cause to collapse by removing underlying support, as by digging away or eroding the foundation.