Definition
To undermine is to weaken something from below while its surface still looks sound. The word is medieval siegecraft: attackers dug mines beneath a castle wall until, untouched from the front, it collapsed into the hollowed ground. Modern undermining keeps that geometry — rumors undermine authority and scandals undermine trust in exactly the same way, by quiet excavation. The damage is invisible while it happens; the wall stands right up until it doesn't.
Examples
- Constant criticism in front of colleagues gradually undermined her confidence.
- Publishing only part of the data would undermine the credibility of the entire study.
- Years of drought have undermined the region's efforts to rebuild its agriculture.
Collocations
undermine confidence·undermine the credibility of·seriously undermine·undermine efforts to·undermine trust
Synonyms
weaken·erode·sabotage·subvert·compromise
Antonyms
strengthen·bolster·reinforce
In TOEFL & IELTS
One of the most useful argument verbs in both exams. TOEFL reading questions hinge on whether new evidence 'supports or undermines' a hypothesis — treat the word as a stance signpost. In IELTS Writing Task 2, 'this policy could undermine public trust' is a high-band way to introduce a drawback. Keep its geometry in mind: it pairs with the foundations of things — trust, authority, credibility, stability — not with their surfaces.