1. (

• stand-in ,
• substitute ,
• relief ,
• reliever ,
• backup ,
• backup_man ,
• fill-in

) someone who takes the place of another (as when things get dangerous or difficult); "the star had a stand-in for dangerous scenes"; "we need extra employees for summer fill-ins" ;

1. (

• substitute ,
• sub ,
• stand_in ,
• fill_in

) be a substitute; "The young teacher had to substitute for the sick colleague"; "The skim milk substitutes for cream;