Pronunciation: (un"dur-mīn' or, esp. for 1, 2, 4, un'dur-mīn"),[key] —v.t.,-mined, -min•ing. 1. to injure or destroy by insidious activity or imperceptible stages, sometimes tending toward a sudden dramatic effect.
2. to attack by indirect, secret, or underhand means; attempt to subvert by stealth.
3. to make an excavation under; dig or tunnel beneath, as a military stronghold.
4. to weaken or cause to collapse by removing underlying support, as by digging away or eroding the foundation.