substitute
substitute - noun
a person or thing that takes or can take the place of another
an athlete who plays only when a starter on the team is replaced
someone who takes the place of another (as when things get dangerous or difficult)
substitute - verb
- put in the place of another; switch seemingly equivalent items
- be a substitute
- act as a substitute
substitute - adjective
- capable of substituting in any of several positions on a team
- serving or used in place of another
- artificial and inferior
substitute - thesaurus
alternate
alternative
backup
deputise
deputize
ersatz
exchange
interchange
relief
reliever
replace
replacement
reserve
sub
utility