involuntary

adjective

in·​vol·​un·​tary (ˌ)in-ˈvä-lən-ˌter-ē 

-ˌte-rē

1

: done contrary to or without choice

2

: compulsory

3

: not subject to control of the will : reflex

involuntarily

(ˌ)in-ˌvä-lən-ˈter-ə-lē 

-ˈte-rə-

adverb

involuntariness

(ˌ)in-ˈvä-lən-ˌter-ē-nəs 

-ˌte-rē-

noun

Synonyms of involuntary

• accidental
• spontaneous
• unwilling
• unintentional
• forced
• coerced

Examples of involuntary in a Sentence

Breathing and circulation are involuntary processes.

When the door burst open, she let out an involuntary shriek.

The lawyer argued that the client's confession was involuntary.

Recent Examples on the Web

Patients stay there for a few days to a week at a time, often until their involuntary commitment expires. — Grant Stringer, Mercury News, 29 June 2026

One change was involuntary after captain César Montes earned a red card and was suspended for tonight's game. — Andrew Greif, NBC news, 19 June 2026

The involuntary drivers of the buses that had become momentary monuments fist-bumped the fans who streamed past them. — Hannah Keyser, CNN Money, 14 June 2026

This can reduce the strain on the electric grid and help prevent the need for involuntary power curtailment or power brownouts, Holran notes. — Karla Walsh, Southern Living, 21 June 2026

Word History

Etymology

Middle English involuntari, from Late Latin involuntarius, from Latin in- + voluntarius voluntary

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing involuntary

• involuntary manslaughter
• involuntary muscle

Rhymes for involuntary

• accretionary
• apothecary
• bicentenary
• certiorari
• concessionary
• concretionary
• confectionary
• confectionery
• constabulary
• contemporary
• deflationary
• depositary

Kids Definition

involuntary

adjective

in·​vol·​un·​tary (ˈ)in-ˈväl-ən-ˌter-ē 

1

: not made or done willingly or from choice : unwilling

2

: being enforced or required : mandatory

3

: not normally under the control of the will

an involuntary response to a stimulus

involuntarily

(ˌ)in-ˌväl-ən-ˈter-ə-lē 

adverb

Medical Definition

involuntary

adjective

in·​vol·​un·​tary (ˈ)in-ˈväl-ən-ˌter-ē 

: not subject to control of the will : reflex

involuntary contractions

Legal Definition

involuntary

adjective

in·​vol·​un·​tary in-ˈvä-lən-ˌter-ē 

: done, made, or initiated contrary to or without one's choice

an involuntary confession

an involuntary lien

an involuntary plaintiff joined in the action

involuntarily adverb