floater

1. A person who physically floats in a gas or liquid.
2. A corpse floating in a body of water. (slang)
3. A person who frequently changes where they live; a drifter, a vagrant. (figuratively)
4. A person who frequently changes employment. (figuratively)
5. 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. (figuratively)
6. An "extra" (male) guest at a party who is asked by the host to entertain the other (often female) guests. (figuratively)
7. 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. (figuratively, slang)
8. A voter who shifts their allegiance from one political party to another, especially (US) one whose vote can be illegally purchased. (figuratively)

Plural floaters