vol·un·tar·y 
(vŏlən-tĕr′ē)
(vŏlən-tĕr′ē)adj.
1. Done or undertaken of one's own free will: a voluntary decision to leave the job.
2. Acting or done willingly and without constraint or expectation of reward: a voluntary hostage; voluntary community work.
3. Normally controlled by or subject to individual volition: voluntary muscle contractions.
4. Capable of making choices; having the faculty of will: "This law of happiness ... resides in the exercise of the active capacities of a voluntary agent" (John Dewey).
5. Supported by contributions or charitable donations rather than by government appropriations: voluntary hospitals.
6. Law
a. Without legal obligation or consideration: a voluntary conveyance of property.
b. Done intentionally but without premeditation or deliberation, as when under the influence of an intense emotional reaction: voluntary manslaughter.
n. pl. vol·un·tar·ies
1. Music
a. A short piece of music, often improvised on a solo instrument, played as an introduction to a larger work.
b. A piece for solo organ, often improvised, played before, during, or after a religious service.
2. A volunteer.
[Middle English, from Latin voluntārius, from voluntās, choice, from velle, vol-, to wish; see wel-1 in the Appendix of Indo-European roots.]
vol′un·tari·ly (-târə-lē) adv.
volun·tar′i·ness n.
Synonyms: voluntary, intentional, deliberate, willful, willing
These adjectives mean being or resulting from one's own free will. Voluntary implies the operation of unforced choice: "Ignorance, when it is voluntary, is criminal" (Samuel Johnson).
Intentional applies to something undertaken to further a plan or realize an aim: "I will abstain from all intentional wrongdoing and harm" (Hippocratic Oath).
Deliberate stresses premeditation and full awareness of the character and consequences of one's acts: taking deliberate and decisive action. Willful implies deliberate, headstrong persistence in a self-determined course of action: a willful waste of time. Willing suggests ready or cheerful acquiescence in the proposals or requirements of another: "The first requisite of a good citizen ... is that he shall be able and willing to pull his weight" (Theodore Roosevelt).
These adjectives mean being or resulting from one's own free will. Voluntary implies the operation of unforced choice: "Ignorance, when it is voluntary, is criminal" (Samuel Johnson).
Intentional applies to something undertaken to further a plan or realize an aim: "I will abstain from all intentional wrongdoing and harm" (Hippocratic Oath).
Deliberate stresses premeditation and full awareness of the character and consequences of one's acts: taking deliberate and decisive action. Willful implies deliberate, headstrong persistence in a self-determined course of action: a willful waste of time. Willing suggests ready or cheerful acquiescence in the proposals or requirements of another: "The first requisite of a good citizen ... is that he shall be able and willing to pull his weight" (Theodore Roosevelt).