What is the meaning of Voluntary?

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

Done by design or intention; intentional.

Working or done without payment.

Endowed with the power of willing.

Of or relating to voluntarism.

Voluntarily.

A short piece of music, often having improvisation, played on a solo instrument.

A volunteer.

A supporter of voluntarism; a voluntarist.

Source: wiktionary.org