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.

---

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

---

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

Hagibis caused enormous damage from rain and wind, Lin said, even though the storm had weakened somewhat before reaching the city.

From Science Daily

If the job market continues to weaken, that will show up more vividly in 2026.

From Los Angeles Times

This included breakdown of the blood-brain barrier, damage to nerve fibers, chronic inflammation, reduced formation of new neurons in the hippocampus, weakened communication between brain cells, and extensive oxidative damage.

From Science Daily

The dollar weakened slightly, including against the Japanese yen.

From The Wall Street Journal

Stein told ProPublica that state residents have suffered, in the form of weakened environmental protections and rising energy costs.

From Salon

Related Words

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