(1):

(n.) One who causes a wreck, as by false lights, and the like.

(2):

(n.) One who searches fro, or works upon, the wrecks of vessels, etc. Specifically: (a) One who visits a wreck for the purpose of plunder. (b) One who is employed in saving property or lives from a wrecked vessel, or in saving the vessel; as, the wreckers of Key West.

(3):

(n.) A vessel employed by wreckers.