Definition of involuntary :
1. Not having will or the power of choice.
2. Not proceeding from choice; done unwillingly; reluctant; compulsory; as, involuntary submission.
3. Not under the influence or control of the will; not voluntary; as, the involuntary movements of the body; involuntary muscle fibers.
automatic, reflex, impulsive, coincidental, planned, impromptu, mechanical, habitual, unbidden, random, unintended, driven, coerced, unwilled, knee-jerk, will-less, willing, nonelective, reflexive, instinctual, goaded, incumbent, mechanic, free, spontaneous, autonomic, instinctive, unvoluntary, unwilling, study at spontaneous, nonvoluntary, by accident, voluntary, robotic, vegetative, forced, peremptory, arbitrary, unpremeditated, unconscious, accidental, uncontrolled, unintentional
required (part of speech: adjective)
inescapable, must, compulsory, pressing, proviso, necessary, indispensable, mandatory, requisite, constraining, inevitable, obligatory, required, imperative, prerequisite, stipulated, essential, binding, inexorable
- Even so, he felt that no small degree of physical danger would attend that presence, particularly if it should really prove, as they could but suspect, that both wife and daughter of the involuntary exile were yonder, among the Aztecans. - "The Lost City", Joseph E. Badger, Jr..
- I knew that my life had hung by a thread while I had been their involuntary host. - "An Autobiography of Buffalo Bill (Colonel W. F. Cody)", Buffalo Bill (William Frederick Cody).
- In trying to pass each other Prue and the preacher fell into an involuntary tango step that delighted the witnesses. - "In a Little Town", Rupert Hughes.