B2a thing or person that is used instead of another thing or person: Tofu can be used as a meat substitute in vegetarian recipes.Vitamins should not be used as a substitute for a healthy diet.Replacing and exchanging›(informalsub)in sports, a player who is used for part of a game instead of another player: Johnson came on as a substitute towards the end of the match.The manager brought on (US alsosent in) another substitute in the final minutes of the game.Replacing and exchangingCompetitors and participants in sports and gamesthere is no substitute for sth›nothing is as good as the stated thing: You can work from plans of a garden, but there's no substitute for visiting the site yourself.Replacing and exchanging›(alsosubstitute teacher, informalsub)US forsupply teacherTeachers