<p><strong>Adjective</strong></p><ul><li>not voluntary; independent of one's will; not by one's own choice.</li><li>unintentional; unconscious.</li><li>occurring independently of or done or occurring without volition.</li></ul><p><strong>Synonyms</strong></p><ul><li>instinctive</li></ul><p><strong>Antonyms</strong></p><ul><li>intentional</li></ul><p><strong>Physiology</strong></p><ul><li>acting independently of or done or occurring without volition.</li></ul><p><strong>Synonyms</strong></p><ul><li>uncontrolled</li><li>reflex</li></ul>