weaken

verb

weak·​en ˈwē-kən 

weakened; weakening

ˈwēk-niŋ,

ˈwē-kə-  ; weakens

transitive verb

1

: to make weak : lessen the strength of

2

: to reduce in intensity or effectiveness

intransitive verb

: to become weak

weakener

ˈwēk-nər

ˈwē-kə- 

noun

Synonyms

• soften
• injure
• debilitate

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.

Recent Examples on the Web

Abandoning recognition can erode motivation, diminish engagement and make employees feel invisible, weakening the cultural fabric and undermining long-term resilience. —Expert Panel®, Forbes.com, 27 June 2025

But in an unexpected ruling in 2023, the Supreme Court declined an invitation to weaken Section 2 of the Voting Rights Act. —June 27, CBS News, 27 June 2025

All components of [Oxford’s] index weakened this month. —Diane Brady, Fortune, 26 June 2025

This weakens our capacity to conduct and publish research, sidelines workforce development programs and puts already vulnerable species at greater risk. —John Racanelli, Baltimore Sun, 26 June 2025

Word History

First Known Use

circa 1529, in the meaning defined at transitive sense 1

Rhymes for weaken

• beacon
• deacon
• archdeacon
• mohican

Kids Definition

weaken

verb

weak·​en ˈwē-kən 

weakened; weakening ˈwēk-(ə-)niŋ 

: to make or become weak or weaker