involuntary

American

[in-vol-uhn-ter-ee] / ɪnˈvɒl ənˌtɛr i /

adjective

not voluntary; independent of one's will; not by one's own choice.

an involuntary listener; involuntary servitude.
unintentional; unconscious.

an involuntary gesture.

Synonyms:

instinctive

Antonyms:

intentional
Physiology. acting independently of or done or occurring without volition.

involuntary muscles.

Synonyms:

uncontrolled, reflex

involuntary British

/ -trɪ, ɪnˈvɒləntərɪ /

adjective

carried out without one's conscious wishes; not voluntary; unintentional
physiol (esp of a movement or muscle) performed or acting without conscious control

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

involuntary Scientific

/ ĭn-vŏl′ən-tĕr′ē /

Not under conscious control. Most of the biological processes in animals that are vital to life, such as contraction of the heart, blood flow, breathing, and digestion, are involuntary and controlled by the autonomic nervous system.

Related Words

See automatic.

Other Word Forms

involuntarily adverb
involuntariness noun

Etymology

Origin of involuntary

From the Late Latin word involuntārius, dating back to 1525–35. See in- ³, voluntary

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Because EMS lacks familiar markers for exhaustion—it’s hard to gauge effort with involuntary muscle contractions—people can unwittingly overdo it.

From The Wall Street Journal • Apr. 1, 2026

A last resort would be a conservatorship, which is an involuntary process and takes place when a person is unable to take care of their finances.

From MarketWatch • Mar. 23, 2026

“California has both the right and the responsibility to ensure that every involuntary residential facility meets fundamental standards of safety, sanitation, and humane treatment.”

From Los Angeles Times • Mar. 6, 2026

A regional court in Katowice sentenced one, who was also charged with causing involuntary manslaughter, to 18 months in prison and barred him from practicing medicine for six years.

From Barron's • Mar. 3, 2026

She could feel his hands give an involuntary tremor.

From "The Golden Compass" by Philip Pullman

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023