To act as a substitute for a person in their role or office
to officially empower and authorize (someone) to act as a substitute in one's role or office
To officially empower, authorize, pronounce, and establish (someone) to be a deputy.
To substitute for; to replace; (theater) to serve as an understudy.
To make one of a party in a bet or other speculation.
To take a side in a dispute.
A substitute; a replacement.