voluntariamente
/bolunˌtaɾjaˈmente/ · B2 · adv
voluntarily
🙋 voluntaria + mente: from Latin voluntas (will) + 'in a mind-way' suffix
Voluntario comes from Latin voluntas, meaning will or wish. Adding -mente (from Latin mens, mind or manner) makes it an adverb: done in a willing manner, by one's own choice. Same root as English volunteer and volition.