What is the meaning of volunteer?

noun

• Military) a person who freely enlists for service.
  • synonyms: military volunteer, voluntary
• A person who performs voluntary work.
  • synonyms: unpaid worker
• A native or resident of Tennessee.
  • synonyms: Tennessean

verb

• Tell voluntarily.
  • usage: "He volunteered the information"
• Agree freely.
  • usage: "She volunteered to drive the old lady home"; "I offered to help with the dishes but the hostess would not hear of it"
  • synonyms: offer
• Do volunteer work.

adjective

• Without payment.
  • usage: "the soup kitchen was run primarily by unpaid helpers"; "a volunteer fire department"
  • synonyms: unpaid