US [.ʌndər’maɪn]
UK [.ʌndə(r)’maɪn]

verb (used with object), undermined, undermining.

  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.