floater

A person who physically floats in a gas or liquid.

A corpse floating in a body of water.

A person who frequently changes where they live; a drifter, a vagrant.

A person who frequently changes employment.

An employee of an organization who does not have fixed tasks to do but fills in wherever needed, usually when someone else is away; also, a short-term employee; a temporary, a temp.

An "extra" (male) guest at a party who is asked by the host to entertain the other (often female) guests.

A person who attaches themselves to a group of people, and who repeatedly shows up at group activities even though this is undesired by the group; a hanger-on.

A voter who shifts their allegiance from one political party to another, especially (US) one whose vote can be illegally purchased.

A person who votes illegally in various electoral districts or polling places, either under a false voter registration or under the name of a properly registered voter who has not yet voted.

A person, such as a delegate to a convention or a member of a legislature, who represents an irregular constituency, such as one formed by a union of the voters of two counties neither of which has a number sufficient to be allowed one (or an extra) representative of its own.