Bit player and Walk-on

Walk-on and bit player are semantically related In some cases you can use "Walk-on" instead a noun phrase "Bit player".

Walk-on noun - Plays a small part in a dramatic production.

Bit player and walk-on are semantically related in person who performs topic. Sometimes you can use "Bit player" instead a noun phrase "Walk-on", if it concerns topics such as person who acts in performance.