rover

1. One who roves: a person or animal that travels around, especially over a wide area, without a fixed destination; a nomad, a roamer, a wanderer.
2. A restless, unsteady person who does not settle down; specifically (historical), a flirtatious, unfaithful man; a rake. (dated) · Near-synonyms: see Thesaurus:libertine· She is a rover and dislikes any sort of ties, physical or emotional.
3. Also rover ticket: a person who has a ticket for an event, performance, etc., but no assigned seat, and so has to find a place to sit or stand.
4. A small manned or unmanned land vehicle for exploring extraterrestrial bodies.
5. A defensive back position whose coverage responsibilities are a combination of those of a cornerback, linebacker, and safety; also, a player playing this position.
6. Chiefly in the plural in the form to shoot at rovers: a target randomly selected by an archer, usually for practice; also, a fixed target for practising long-distance shooting.
7. A position that is one of three of a team's followers making up a ruck, who follow the ball around the ground; also, a player playing this position, who is generally fast and skilful at receiving the ball, and formerly of shorter stature.
8. In full rover ball: a ball which has passed through all the hoops and would peg out if it hit the stake but is continued in play to help fellow players or obstruct opposing players; also, the player of such a ball.

Plural rovers