1
- a person who freely offers to take part in an enterprise or undertake a task志愿者。
1.1
- a person who works for an organization without being paid自愿无偿服务者。
1.2
- a person who freely enrols for military service rather than being conscripted, especially a member of a force formed by voluntary enrolment and distinct from the regular army志愿兵。
1.3
- a plant that has not been deliberately planted自生植物。
2
- Law a person to whom a voluntary conveyance or deposition is made【律】无因受益人。
no obj.
1- freely offer to do something自愿：
140 men and women volunteered for redundancy
140个男子和女子自愿下岗
with infinitive I rashly volunteered to be a contestant.我草率地主动提出参加竞赛。
1.1
- with obj. offer (help) in such a way主动提供（帮助）：
he volunteered his services as a driver for the convoy.
他自愿为车队当司机。
1.2
- reporting verb say or suggest something without being asked主动说出（或建议）：
with obj. it never paid to volunteer information主动提供信息向来都是没好处的
with direct speech 'Her name's Louise, ' Christina volunteered.“她叫路易丝,"克里斯蒂娜主动说道。
1.3
- work for an organization without being paid自愿无偿服务。
1.4
- with obj. commit (someone) to a particular undertaking, typically without consulting them（尤指未经协商）使（某人）承担某事：
he was volunteered for parachute training by friends.
朋友代他承诺参加跳伞训练。
词源
late 16th cent. （as a noun， with military reference）： from French volontaire 'voluntary'. The change in the ending was due to association with -EER.