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

The first-quarter boom in U.S. trade is weakening, with merchandise trade somewhat atypically declining for the second straight month, according to my analysis of the the most recent U.S. Census Bureau data. —Ken Roberts, Forbes.com, 9 July 2025

The June jobs report showed strong headline numbers, but the underlying data pointed to a weakening labor market. —Danny Bakst, Fortune, 9 July 2025

Iran's Supreme Leader Ayatollah Ali Khamenei is 86 years-old and his political power is weakened following the short war with Israel. —Jackie Northam, NPR, 9 July 2025

Many fans liked that pairing, but others were overall dissatisfied with the new Casa Amor format, which many felt weakened the loyalty test that the challenge typically creates. —Daysia Tolentino, EW.com, 8 July 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