undermine

[ uhn-der-mahyn or especially for 1, 2, 4, uhn-der-mahyn ]
/ ˌʌn dərˈmaɪn or especially for 1, 2, 4, ˈʌn dərˌmaɪn /

verb (used with object), un·der·mined, un·der·min·ing.

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.

Origin of undermine

First recorded in 1300–50, undermine is from the Middle English word underminen. See under-, mine2

OTHER WORDS FROM undermine

un·der·min·er, noun un·der·min·ing·ly, adverb

Example sentences from the Web for undermining

British Dictionary definitions for undermining

undermine
/ (ˌʌndəˈmaɪn) /

verb (tr)

(of the sea, wind, etc) to wear away the bottom or base of (land, cliffs, etc)
to weaken gradually or insidiously their insults undermined her confidence
to tunnel or dig beneath

Derived forms of undermine

underminer, noun