voluntary

adj

1. Done, given, or acting of one's own free will.

   “September 10, 1828, Nathaniel William Taylor, Sermon delivered in the Chapel of Yale College That sin or guilt pertains exclusively to voluntary action is the true principle of orthodoxy.”

   “She fell, to lust a voluntary prey.”

2. Done by design or intention; intentional.

   “If a man accidentally kills another by lopping a tree, it is not voluntary manslaughter.”

3. Working or done without payment.

   “Wikimedia is a voluntary service.”

4. Endowed with the power of willing.

   “[…] God did not work as a necessary, but a voluntary agent, intending before-hand, and decreeing with himself, that which did outwardly proceed from him.”

5. Of or relating to voluntarism.

   “a voluntary church, in distinction from an established or state church”

adv

1. (obsolete)Voluntarily.

   “And all that els was pretious and deare, / The sea unto him voluntary brings [...].”

noun

1. A short piece of music, often having improvisation, played on a solo instrument.
2. A volunteer.
3. A supporter of voluntarism; a voluntarist.