Synonym: automatic, compulsive, forced, instinctive, mechanical, reflex, spontaneous, unconscious, unintentional, unthinking, unwilling. Antonym: voluntary. Similar words: voluntary, volunteer, counterrevolutionary, involve, involved, convolute, convoluted, involvement. Meaning: [ɪn'vɑlənterɪ /-'vɒləntrɪ] 
adj. 1. not subject to the control of the will 2. controlled by the autonomic nervous system; without conscious control.
adj. 1. not subject to the control of the will 2. controlled by the autonomic nervous system; without conscious control. 
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121. Tourette syndrome is a neurological disorder that can cause involuntary tics such as coughing, yelling, head jerking and blinking.
122. A sudden, involuntary, spasmodic muscular contraction causing severe pain, often occurring in the leg or shoulder as the result of strain or chill.
123. Orgasm consists of involuntary contraction of the pelvic muscles and erotic pleasure.
124. Tickling thus provokes rhythmic , vocalized, expiratory and involuntary actions – better known as laughter.
125. Following involuntary hospitalizations , Sister 1 was diagnosed with schizophrenia, chronic undifferentiated type.
More similar words: voluntary, volunteer, counterrevolutionary, involve, involved, convolute, convoluted, involvement, revolutionary, sedentary, momentary, commentary, elementary, rudimentary, documentary, complementary, invoke, in vogue, blunt, invocation, volume, sales invoice, voluble, evolution, revolution, voluptuous, voluminous, volubility, devolution, revolutionize.