Meaning of “volunteer” - Learner’s Dictionary

volunteer

noun [ C ] uk us /ˌvɒlənˈtɪər/
NOT PAID

B2 someone who does work without being paid, especially work that involves helping people:

a Red Cross volunteer
NOT FORCED

someone who does or gives something because they want to and not because they have been forced to:

Any volunteers to help me move these books?

(Definition of “volunteer noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)