benchwarmer

or bench warm·er, bench-warm·er

[ bench-wawr-mer ]
/ ˈbɛntʃˌwɔr mər /

noun Sports.

a substitute who rarely gets to play in a game.

Origin of benchwarmer

First recorded in 1890–95; bench + warmer
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019