WordNet sense 1 ((military) a person who freely enlists for service):

military volunteer

WordNet sense 2 (a person who performs voluntary work):

unpaid worker

WordNet sense 3 (a native or resident of Tennessee):

Tennessean

WordNet sense 4 (without payment):

unpaid

WordNet sense 5 (of your own free will or design; not forced or compelled):

voluntary

WordNet sense 6 (agree freely):

offer