/plum"euhr/ , n.
1. a person who installs and repairs piping, fixtures, appliances, and appurtenances in connection with the water supply, drainage systems, etc., both in and out of buildings.
2. Slang. an undercover operative or spy hired to detect or stop leaks of news or secret information, often using questionable or illegal methods, as illegal entry or wiretapping.
3. Obs. a worker in lead or similar metals.
[ 1375-1425; 1965-70 for def. 2; late ME, sp. var. of ME plowber plumbarius leadworker; r. ME plummer plummier 2 ]