(of a person or action) acting or done willingly, without being forced
acting or done without payment; controlled or supported by people who give their money, services, etc., of their own free will
done on purpose
"man is a voluntary agent"
"participation was voluntary"
"voluntary manslaughter"
"voluntary generosity in times of disaster"
"voluntary social workers"
"a voluntary confession"
"voluntary motions"
"voluntary muscles"
Were faith not voluntary, it could not be praised.
出自: J. Ruskin