Merriam-Webster Collegiate Dictionary - plumber

 noun  Etymology: Middle English, from Anglo-French plummer, plomner, from Latin plumbarius, from plumbum  Date: 15th century  1. a dealer or worker in lead  2. one who installs, repairs, and maintains piping, fittings, and fixtures involved in the distribution and use of water in a building  3. a person whose job is to prevent or put an end to leaks of sensitive information