walk-on

名词noun

1. 1(sports) A student athlete who wants to try out for a college sports or athletic team without the benefit of a scholarship or having been recruited.
2. 2(theater, film) An actor of a small (or "bit") part in a theatrical production or film, often without speaking lines.
3. 3chiefly attributiveSuch a part in a play or film.
4. 4One who arrives and boards transport (such as a train or ferry) without having booked in advance.