"Volunteer" is a word in LAW AND LEGAL, ENGLISH

In conveyancing, one

Of or pertaining to a volunteer or volunteers;
consisting of volunteers; voluntary; as, volunteer companies; volunteer
advice.

One who enters into service voluntarily, but who, when
in service, is subject to discipline and regulations like other
soldiers; -- opposed to conscript; specifically, a voluntary member of
the organized militia of a country as distinguished from the standing
army.

A grantee in a voluntary conveyance; one to whom a
conveyance is made without valuable consideration; a party, other than
a wife or child of the grantor, to whom, or for whose benefit, a
voluntary conveyance is made.

To offer or bestow voluntarily, or without
solicitation or compulsion; as, to volunteer one's services.

One who enters into, or offers for, any service of his
own free will.

To enter into, or offer for, any service of one's own
free will, without solicitation or compulsion; as, he volunteered in
that undertaking.