involuntary
UK: ɪnˈvɒləntəri | US: ɪnˈvɑːlənteri
adj. not done by choice; unintentional or reflexive
adj. (biology) controlled by autonomic nerves, not conscious will
The word "involuntary" combines the Latin prefix in- (meaning "not") with voluntary, derived from Latin voluntarius ("of one’s free will"). The root volunt- traces back to voluntas ("will"), linked to velle ("to wish"). The term evolved in Middle English to describe actions lacking conscious intent, reflecting a logical negation of voluntary control.
An involuntary shudder ran down her spine when she heard the loud noise.
Breathing is mostly an involuntary process controlled by the brainstem.
His involuntary confession surprised everyone in the courtroom.
The patient’s involuntary muscle spasms required medical attention.
She gave an involuntary smile when she saw the puppy.