Done or undertaken of one's own free will: a voluntary decision to leave the job. Acting or done willingly and without constraint or expectation of reward: a voluntary hostage; voluntary community work. Normally controlled by or subject to individual volition: voluntary muscle contractions. Capable of making choices; having the faculty of will. Supported by contributions or charitable donations rather than by government appropriations: voluntary hospitals. Law Without legal obligation or consideration: a voluntary conveyance of property. Law Done deliberately; intentional: voluntary manslaughter. Music A short piece of music, often improvised on a solo instrument, played as an introduction to a larger work. Music A piece for solo organ, often improvised, played before, during, or after a religious service. A volunteer.