Source : Webster's Revised Unabridged Dictionary (1913)

Voluntary \Vol"un*ta*ry\, a. [L. voluntarius, fr. voluntas will,
   choice, from the root of velle to will, p. pr. volens; akin
   to E. will: cf. F. volontaire, Of. also voluntaire. See
   {Will}, v. t., and cf. {Benevolent}, {Volition},
   {Volunteer}.]
   1. Proceeding from the will; produced in or by an act of
      choice.

            That sin or guilt pertains exclusively to voluntary
            action is the true principle of orthodoxy. --N. W.
                                                  Taylor.

   2. Unconstrained by the interference of another; unimpelled
      by the influence of another; not prompted or persuaded by
      another; done of his or its own accord; spontaneous;
      acting of one's self, or of itself; free.

            Our voluntary service he requires.    --Milton.

            She fell to lust a voluntary prey.    --Pope.

   3. Done by design or intention; intentional; purposed;
      intended; not accidental; as, if a man kills another by
      lopping a tree, it is not voluntary manslaughter.

   4. (Physiol.) Of or pertaining to the will; subject to, or
      regulated by, the will; as, the voluntary motions of an
      animal, such as the movements of the leg or arm (in
      distinction from involuntary motions, such as the
      movements of the heart); the voluntary muscle fibers,
      which are the agents in voluntary motion.

   5. Endowed with the power of willing; as, man is a voluntary
      agent.

            God did not work as a necessary, but a voluntary,
            agent, intending beforehand, and decreeing with
            himself, that which did outwardly proceed from him.
                                                  --Hooker.

   6. (Law) Free; without compulsion; according to the will,
      consent, or agreement, of a party; without consideration;
      gratuitous; without valuable consideration.

   7. (Eccl.) Of or pertaining to voluntaryism; as, a voluntary
      church, in distinction from an established or state
      church.

   {Voluntary affidavit} or {oath} (Law), an affidavit or oath
      made in extrajudicial matter.

   {Voluntary conveyance} (Law), a conveyance without valuable
      consideration.

   {Voluntary escape} (Law), the escape of a prisoner by the
      express consent of the sheriff.

   {Voluntary jurisdiction}. (Eng. Eccl. Law) See {Contentious
      jurisdiction}, under {Contentious}.

   {Voluntary waste}. (Law) See {Waste}, n., 4.

   Syn: See {Spontaneous}.