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 Fed sees a labor market that isn’t weakening and the key drivers of inflation are still likely to keep prices elevated, Oanda analyst Edward Moya says in a research note. WSJ, 22 Sep. 2023 Shigella spreads easily and is especially dangerous for those whose immune systems are weakened by illness or medical treatment. Melody Petersen, Los Angeles Times, 21 Sep. 2023 The rain and gusty winds will persist throughout Saturday and then likely weaken by the evening. Emily Shapiro, ABC News, 21 Sep. 2023 These risks seem to cancel out evidence of alcohol's cardiovascular benefits, which was weakened anyway when researchers did more nuanced studies. Lydia Denworth, Scientific American, 21 Sep. 2023 This is especially true if there are other health factors at play that may be already weakening the immune system. Lauryn Higgins, Health, 20 Sep. 2023 Also missing from the list was UK prime minister Rishi Sunak, who is facing a backlash at home over plans to weaken the country’s climate commitments. Rachel Ramirez, CNN, 20 Sep. 2023 Both trends could keep inflation and the Fed's interest rates high enough and long enough to weaken household and corporate spending and the economy as a whole. Christopher Rugaber The Associated Press, Arkansas Online, 20 Sep. 2023 But a key provision of the bipartisan RECOUP Act making its way through Congress as a response to SVB’s failure could actually end up significantly weakening the stability of the financial system. Dan Katz, National Review, 18 Sep. 2023 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 28 Sep. 2023.

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

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