weaken

American  

[wee-kuhn] / ˈwi kən /

verb (used with object)

1. to make weak or weaker.

   Synonyms:

   invalidate, minimize, impair, reduce, lower, diminish, lessen, deplete, exhaust, sap, undermine, enervate, debilitate, enfeeble

   Antonyms:

   strengthen

2. Phonetics. to change (a speech sound) to an articulation requiring less effort, as from geminate to nongeminate or from stop to fricative.

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verb (used without object)

1. to become weak or weaker.

   Synonyms:

   sap, undermine, enervate, debilitate, enfeeble, invalidate, minimize, impair, reduce, lower, diminish, lessen, deplete, exhaust

   Antonyms:

   strengthen

weaken British  

/ ˈwiːkən /

verb

1. to become or cause to become weak or weaker

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Other Word Forms

• reweaken verb
• unweakened adjective
• unweakening adjective
• weakener noun

Etymology

Origin of weaken

First recorded in 1520–30; weak + -en ¹

Example Sentences

It can also weaken statistical results and fails to reveal how languages change over time.

From Science Daily • Apr. 5, 2026

Rather, recession hawks should keep an eye on compounding jolts that could simultaneously weaken the economy and the labor market, he argues.

From Barron's • Apr. 3, 2026

—The dollar rose as doubts over a swift end to the Iran war weaken risk sentiment and lift oil prices.

From The Wall Street Journal • Apr. 2, 2026

And, when investors’ trust in the published net asset values starts to weaken, it can trigger a feedback loop of redemption requests.

From MarketWatch • Mar. 31, 2026

The doorway behind her was blocked, but in theory, if the room started to collapse, those bricks should weaken and crumble.

From "The Mark of Athena" by Rick Riordan

Related Words

• abate
• decline
• decrease
• depress
• dilute
• diminish
• dwindle
• halt
• impair
• lessen
• lower
• reduce
• sap
• soften
• undermine
• wane