1. (n.) The act of substituting or putting one person or thing in the place of another; as, the substitution of an agent, attorney, or representative to act for one in his absence; the substitution of bank notes for gold and silver as a circulating medium.

2. (n.) The state of being substituted for another.

3. (n.) The office or authority of one acting for another; delegated authority.

4. (n.) The designation of a person in a will to take a devise or legacy, either on failure of a former devisee or legatee by incapacity or unwillingness to accept, or after him.

5. (n.) The doctrine that Christ suffered vicariously, being substituted for the sinner, and that his sufferings were expiatory.

6. (n.) The act or process of substituting an atom or radical for another atom or radical; metathesis; also, the state of being so substituted. See Metathesis.

agent alienation alternate alternative amends analogy atonement autism autistic thinking avoidance mechanism backup balancing blame-shifting change changeling changing commutation comparison compensation copy counteraction counterbalancing counterfeit decompensation defense mechanism deputy dereism dereistic thinking displacement dissociation double dummy emotional insulation equal equivalent ersatz escape escape into fantasy escape mechanism escapism exchange expiation fake fantasizing fantasy fill-in flight ghost ghostwriter imitation indemnification indemnity interchange interchanging isolation lex talionis locum tenens makeshift metaphor metonymy negativism next best thing offsetting overcompensation personnel phony pinch hitter projection proxy psychotaxis rationalization recompense rectification redress relief reparation repayment replacement replacing representative reserves resistance restitution retaliation revenge ringer satisfaction second string secondary sign sociological adjustive reactions spares stand-in sub sublimation substituent substitute succedaneum superseder supplanter supplanting surrogate swap swapping switch switching symbol synecdoche third string token understudy utility player vicar vice-president vice-regent wish-fulfillment fantasy wishful thinking withdrawal