volunteer

/ˌvɑlənˈtɪr/
adjective
  1. Describing a person who serves without pay, or an activity done without pay.
    • She joined a volunteer program teaching English abroad.
    • The event was organized by a volunteer committee.
    • The volunteer firefighters arrived at the scene within minutes.
verb
  1. To freely offer to do something, especially without expecting payment.
    • He volunteered to drive the kids to soccer practice.
    • She volunteered at the food bank every Saturday.
    • Many neighbors volunteered their time to rebuild the playground.
  2. To offer something (such as information or help) without being asked.
    • No one asked, but he volunteered his opinion anyway.
    • She volunteered a suggestion for improving the project.
    • The witness volunteered important details to the police.
Synonyms
noun
  1. A person who freely offers to do something without being paid or forced.
    • Volunteers helped clean up the park after the storm.
    • The shelter relies on volunteers to walk the dogs every morning.
    • She became a volunteer at the local hospital after retiring.