adj.
  - done, given, or acting of one's own free will. ▸Physiology  under the conscious control of the brain. 
- working or done without payment. ▸Law  (of a conveyance or disposition) made without return in money or other consideration. 
n.
 (pl. voluntaries)
  - an organ solo played before, during, or after a church service. ▸historical a piece of music performed extempore or composed in a free style. 
- (in a competition) a special performance left to the performer's choice.
Derivative
  
    - voluntarily adv.
- voluntariness n.
 
  Etymology
  ME: from OFr. volontaire or L. voluntarius, from voluntas ‘will’.