second-stringer

Meaning

1. noun A person who plays second string. A person who is kept on a sports team as a backup in case a "first-string" player is unavailable.
2. noun A person who is not good enough to be considered proficient but may be useful as a backup.

Similar words

second-teamer firststringer second violinist stringer underactor runner-up understudy vice-champion first-teamer backstager