— second-string , adj. — second-stringer , n.
1. Sports. the squad of players available either individually or as a team to replace or relieve those who start a game.
2. a secondary position, status, or group, as in a level of corporate management.
[ 1635-45 in sense "backup, resort," alluding to a second bowstring; 1860-65, applied to racehorses; 1950-55, to sports teams ]