verb un·der·mine \ ˌən-dər-ˈmīn , ˈən-dər-ˌmīn \
|Updated on: 22 Jul 2018

Definition of undermine

undermined; undermining; undermines
1 : to subvert or weaken insidiously or secretly
  • trying to undermine his political rivals
2 : to weaken or ruin by degrees
3 : to wash away supporting material from under
4 : to excavate the earth beneath : form a mine under : sap

Examples of undermine in a Sentence

  1. She tried to undermine my authority by complaining about me to my boss.

  2. The events of the past year have undermined people's confidence in the government.

  3. When we published the early results of our investigation, the British public learned for the first time of the Ring of Five’s betrayal. Philby’s attempts to undermine Western security, we found, had been constant and relentless, his access to our secrets apparently total. We homed in on two examples. The first was his job in charge of SIS’s anti-Soviet section. If the officer in charge of Britain’s anti-Soviet plans was a Soviet agent himself, how could any anti-Soviet operation succeed? —“Turning the Philby Case on Its Head” P. 51, Phillip Knightley, THE NEW YORK REVIEW OF BOOKS Vol. LIV No. 7, April 26, 2007

  4. Now they just have been getting beat. Weakened by injuries to center Steven Reinprecht and Mike Comrie and right wing Shane Doan, and undermined by erratic goaltending from Curtis Joseph, the Coyotes are, as one player said, “out of sync.” —“Hockey” P. 59, Michael Farber, SPORTS ILLUSTRATED Vol. 105 No. 20, November 20, 2006

  5. “ ‘…. Cluny returned by night, and with his band of rats gnawed away and undermined much of the wooden shoring. This caused the mine to collapse the next day, killing the owners.’” —“Chapter 7” The Wall P. 37, REDWALL, Brian Jacques, FIREBIRD Published by Penguin Group (1986) 2002

  6. As bin Laden’s admirers appear to grow in number, the question is again being asked: Can the Saudi royals withstand the increasing pressures undermining political stability in the most vital energy-producing region of the world? —“The Uneasy Ally” P. 61, Scott MacLeod, TIME Vol. 158 No. 17, October 15, 2001

  7. “It isn’t funny!” Mr. Weasley shouted. “That sort of behavior seriously undermines wizards-Muggle relations! I spend half my life campaigning against the mistreatment of Muggles, and my own sons —” —Chapter Five “Weasley’s Wizard Wheezes” p. 53, HARRY POTTER AND THE GOBLET OF FIRE, J. K. Rowling, Arthur A. Levine Books 2000

  8. ... the "politically driven 'reformation'" of the American military over the past decade through a policy of integrating women completely. This policy, she says, has undermined readiness. —"Make War, Not Nice!" P. 12, Carol Gilligan, THE NEW YORK TIMES BOOK REVIEW, May 7, 2000

  9. Having condemned scores of humble men and women, he denounced Count Henry of Sayn. Local Church and State leaders were horrified: inquisitors were supposed to underpin the social order not undermine it. An assembly at Mainz reversed Conrad’s decision but he insisted that it had no power to do so. His enemies wasted no more time on argument. Conrad and his party were attacked and murdered as they left the city. After this, the Inquisition was never accepted throughout most of Germany. —“Chapter Nine” P. 229, REFORMATIONS, Felipe Fernández-Armesto (Brit) & Derek Wilson (Brit), Scribner 270 F39r (1996) 1997

Recent Examples of undermine from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'undermine.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of undermine

14th century

in the meaning defined at sense 4

See Words from the same year
NEW! Time Traveler

Synonym Discussion of undermine

weaken, enfeeble, debilitate, undermine, sap, cripple, disable mean to lose or cause to lose strength or vigor. weaken may imply loss of physical strength, health, soundness, or stability or of quality, intensity, or effective power.
    • a disease that weakens the body's defenses
enfeeble implies a condition of marked weakness and helplessness.
    • enfeebled by starvation
debilitate suggests a less marked or more temporary impairment of strength or vitality.
    • the debilitating effects of surgery
undermine and sap suggest a weakening by something working surreptitiously and insidiously.
    • a poor diet undermines your health
    • drugs had sapped his ability to think
cripple implies causing a serious loss of functioning power through damaging or removing an essential part or element.
    • crippled by arthritis
disable suggests bringing about impairment or limitation in a physical or mental ability.
    • disabled by an injury sustained at work

UNDERMINE Defined for English Language Learners


Definition of undermine for English Language Learners

  • : to make (someone or something) weaker or less effective usually in a secret or gradual way

UNDERMINE Defined for Kids


verb un·der·mine \ ˌən-dər-ˈmīn \

Definition of undermine for Students

undermined; undermining
1 : to dig out or wear away the supporting earth beneath
  • Erosion undermined the wall.
2 : to weaken secretly or little by little
  • Their criticisms undermine my confidence.

Seen and Heard

What made you want to look up undermine? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!


to hasten

Get Word of the Day daily email!

Test Your Vocabulary

Test Your Emoji Exceptionalism

  • test-your-emoji-exceptionalism-written-with-a-lot-of-emoji
  • What is this emoji intended to represent: 🤳
True or False

Test your knowledge - and maybe learn something along the way.


Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!