Voluntary

adjective
1.
done, made, brought about, undertaken, etc., of one’s own accord or by free choice:
a voluntary contribution.
2.
of, relating to, or acting in accord with the will:
voluntary cooperation.
3.
of, relating to, or depending on voluntary action:
voluntary hospitals.
4.
Law.

acting or done without compulsion or obligation.
done by intention, and not by accident:
voluntary manslaughter.
made without valuable consideration:
a voluntary settlement.

5.
Physiology. subject to or controlled by the will.
6.
having the power of willing or choosing:
a voluntary agent.
7.
proceeding from a natural impulse; spontaneous:
voluntary laughter.
noun, plural voluntaries.
8.
something done voluntarily.
9.
a piece of music, frequently spontaneous and improvised, performed as a prelude to a larger work, especially a piece of organ music performed before, during, or after an office of the church.
adjective
1.
performed, undertaken, or brought about by free choice, willingly, or without being asked: a voluntary donation
2.
(of persons) serving or acting in a specified function of one’s own accord and without compulsion or promise of remuneration: a voluntary social worker
3.
done by, composed of, or functioning with the aid of volunteers: a voluntary association
4.
endowed with, exercising, or having the faculty of willing: a voluntary agent
5.
arising from natural impulse; spontaneous: voluntary laughter
6.
(law)

acting or done without legal obligation, compulsion, or persuasion
made without payment or recompense in any form: a voluntary conveyance

7.
(of the muscles of the limbs, neck, etc) having their action controlled by the will
8.
maintained or provided by the voluntary actions or contributions of individuals and not by the state: voluntary schools, the voluntary system
noun (pl) -taries
9.
(music) a composition or improvisation, usually for organ, played at the beginning or end of a church service
10.
work done without compulsion
11.
(obsolete) a volunteer, esp in an army

voluntary vol·un·tar·y (vŏl’ən-těr’ē)
adj.

Arising from or acting on one’s own free will.

Normally controlled by or subject to individual volition, as of respiration.

Capable of making choices; having the faculty of will.