Synonyms of the word

volitional

• adj. done by conscious, personal choice; not based on external principles.
• adj. done intentionally, not by accident.
• adj. (rare) pertaining to volition.

voluntary

• adj. Done, given, or acting of one's own free will.
• adj. Done by design or intention; intentional.
• adj. Working or done without payment.
• adj. Endowed with the power of willing.
• adj. Of or relating to voluntarism.
• adv. (obsolete) Voluntarily.
• n. (music) A short piece of music, often having improvisation, played on a solo instrument.
• n. A volunteer.

willing

• adj. Ready to do something that is not (can't be expected as) a matter of course.
• n. (rare or obsolete) The execution of a will.
• v. present participle of will.