weaken

verb weak·en \ˈwē-kən\

: to make (something or someone) weaker, less forceful, less effective, etc.

: to become weaker, less forceful, less effective, etc.

of money : to decrease in value when compared to money from other countries

weak·enedweak·en·ing \ˈwēk-niŋ, ˈwē-kə-\

Full Definition of WEAKEN

transitive verb

: to make weak : lessen the strength of

: to reduce in intensity or effectiveness

intransitive verb

: to become weak

— weak·en·er \ˈwēk-nər, ˈwē-kə-\ noun

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First Known Use of WEAKEN

1530

Related to WEAKEN

Synonyms: debilitate, devitalize, enervate, enfeeble, etiolate, prostrate, sap, soften, tire, waste

Antonyms: beef (up), fortify, strengthen

Synonym Discussion of WEAKEN

weaken, enfeeble, debilitate, undermine, sap, cripple, 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 an obvious and pitiable condition of 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>. cripple implies causing a serious loss of functioning power through damaging or removing an essential part or element <crippled by arthritis>. disable suggests a usually sudden crippling or enfeebling <disabled soldiers received an immediate discharge>.