substitute definition

1. a person or thing that takes or can take the place of another
2. an athlete who plays only when a starter on the team is replaced
3. put in the place of another; switch seemingly equivalent items
• examples: the con artist replaced the original with a fake Rembrandt
• examples: substitute regular milk with fat-free milk
• examples: synonyms can be interchanged without a changing the context's meaning
4. be a substitute
• examples: The young teacher had to substitute for the sick colleague
• examples: The skim milk substitutes for cream--we are on a strict diet
5. act as a substitute
• examples: She stood in for the soprano who suffered from a cold