An actor who performs on stage, especially one who is part of an acting troupe.
An actor of a small (or "bit") part in a theatrical production or film, often without speaking lines.
One who arrives and boards transport (such as a train or ferry) without having booked in advance.
A student athlete who wants to try out for a college sports/athletic team without the benefit of a scholarship or having been recruited.
Such a part in a play or film.