voluntary
n.n. done or given because you want to do it, not because you are forced to. You do not get paid for this kind of work.
n. performed, undertaken, or brought about by free choice rather than compulsion. Often used to describe unpaid labor or contributions to a cause.
She does voluntary work at the local animal shelter.
The company asked for voluntary redundancies to avoid forced layoffs during the financial crisis.
While the participation was technically voluntary, the social pressure from the management made many employees feel that declining the invitation would damage their career prospects.
From Middle English voluntarie, from Old French volontaire, from Latin voluntārius (“willing, of free will”), from voluntās (“will, choice, desire”), from volēns, present participle of volo (“to will”). Displaced native Old English selfwille (literally “self-willed”).
Commonly modifies nouns like 'work', 'service', or 'contribution'.
I did a voluntary in the hospitalI did voluntary work in the hospitalIn general contexts, 'voluntary' is an adjective and requires a noun like 'work' or 'service' to follow it.