Definition of "deputy"

One appointed as the substitute of others, and empowered to act for them, in their name or their behalf; a substitute in office.  examples

(mining, historical) A person employed to install and remove props, brattices, etc. and to clear gas, for the safety of the miners.

(government) The name for a member of parliament in some countries.

1. A member of the French National Assembly.  examples

2. (historical) A member of the French Chamber of Deputies, formerly called Corps Législatif.

3. (Ireland, often capitalized) A member of Dáil Éireann, or the title of a member of Dáil Éireann.  examples

(US) a law enforcement officer who works for the county sheriff's office; a deputy sheriff or sheriff's deputy; the entry level rank in such an agency.  examples

(informal, nonstandard) to deputise