weak·​en ˈwē-kən How to pronounce weaken (audio)
weakened; weakening
ˈwē-kə- How to pronounce weaken (audio)
; weakens

transitive verb

: to make weak : lessen the strength of
: to reduce in intensity or effectiveness

intransitive verb

: to become weak
ˈwē-kə- How to pronounce weaken (audio)
Choose the Right Synonym for weaken

weaken, enfeeble, debilitate, undermine, sap, 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

disable suggests bringing about impairment or limitation in a physical or mental ability.

disabled by an injury sustained at work

Examples of weaken in a Sentence

The disease weakens the immune system. Some are concerned that the increase in taxes will weaken the economy. The beams had been weakened by water damage. efforts to weaken environmental laws The recent setbacks have not weakened our resolve. These kinds of contradictions weaken your argument. The disease causes the immune system to weaken. The dollar has continued to weaken against the euro. Lower interest rates have weakened the dollar. See More
Recent Examples on the Web The scandal could also weaken Hungary’s bid to gain more influence in Brussels in the upcoming European elections. Christian Edwards, CNN, 17 Feb. 2024 Both Japan and the United Kingdom said Thursday their economies likely weakened during the final three months of 2023. Stan Choe, Fortune, 16 Feb. 2024 Gambling weakens the bonds upon which strong societies depend. Eleanor Dearman, Fort Worth Star-Telegram, 15 Feb. 2024 For years, Rocha led behind-the-scene efforts to buy claims on U.S. properties in Cuba that had been confiscated without compensation during the early days of Fidel Castro’s revolution and to promote investment on the island to weaken the U.S. economic embargo on the island. Nora Gámez Torres, Miami Herald, 14 Feb. 2024 The economic aspects surrounding holidays like Valentine's Day draw the focus away from human relationships, possibly weakening other forms of social interaction, according to Forbes. Maeghan Dolph, Fox News, 14 Feb. 2024 The Fed is concerned that a weakening jobs market may force its hand in prompting interest rate cuts. Simon Moore, Forbes, 10 Feb. 2024 Freezing temperatures made living conditions inside the plane fuselage incredibly harsh, and the survivors were weakened by exposure. Madeleine Kearns, National Review, 8 Feb. 2024 Water seeps into cracks in the pavement, weakening the layers beneath the surface. Jon Healey, Los Angeles Times, 7 Feb. 2024 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'weaken.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1530, in the meaning defined at transitive sense 1

Time Traveler
The first known use of weaken was in 1530

Dictionary Entries Near weaken

Cite this Entry

“Weaken.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/weaken. Accessed 26 Feb. 2024.

Kids Definition


weak·​en ˈwē-kən How to pronounce weaken (audio)
weakened; weakening ˈwēk-(ə-)niŋ How to pronounce weaken (audio)
: to make or become weak or weaker

More from Merriam-Webster on weaken

Last Updated: - Updated example sentences
Love words? Need even more definitions?

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