See more synonyms for involuntary on
  1. not voluntary; independent of one's will; not by one's own choice: an involuntary listener; involuntary servitude.
  2. unintentional; unconscious: an involuntary gesture.
  3. Physiology. acting independently of or done or occurring without volition: involuntary muscles.

Origin of involuntary

From the Late Latin word involuntārius, dating back to 1525–35. See in-3, voluntary
Related formsin·vol·un·tar·i·ly [in-vol-uhn-ter-uh-lee, -vol-uhn-tair-] /ɪnˈvɒl ənˌtɛr ə li, -ˌvɒl ənˈtɛər-/, adverbin·vol·un·tar·i·ness, noun

Synonyms for involuntary

See more synonyms for on

Synonym study

1, 3. See automatic.

Antonyms for involuntary Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for involuntarily

Contemporary Examples of involuntarily

Historical Examples of involuntarily

  • Involuntarily I gave way, and in she crept like a big baby, Biddy coming after.

    It Happened in Egypt

    C. N. Williamson

  • Then there was a little crack, and Mary involuntarily looked at the lamp chimney.

    Tiverton Tales

    Alice Brown

  • But as she sat "hooking-in," the window was darkened, and involuntarily she lifted her eyes.

    Meadow Grass

    Alice Brown

  • She turned the horse about, and involuntarily struck him with her little switch.

    Meadow Grass

    Alice Brown

  • Involuntarily he shrank back a pace, to the first step from the top.

    The Black Bag

    Louis Joseph Vance

British Dictionary definitions for involuntarily


  1. carried out without one's conscious wishes; not voluntary; unintentional
  2. physiol (esp of a movement or muscle) performed or acting without conscious control
Derived Formsinvoluntarily, adverbinvoluntariness, noun
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

Word Origin and History for involuntarily



mid-15c., from Late Latin involuntarius "involuntary," from in- "not, opposite of" (see in- (1)) + Latin voluntarius (see voluntary). Related: Involuntarily.

Online Etymology Dictionary, © 2010 Douglas Harper

involuntarily in Medicine


  1. Not subject to control of the volition.
  2. Acting or done without or against one's will.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

involuntarily in Science


  1. 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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.