1640s, from French lampon (17c.), of unknown origin, said by French etymologists to be from lampons "let us drink," popular refrain for scurrilous 17c. songs, from lamper "to drink, guzzle," a nasalized form of laper "to lap," from a Germanic source akin to lap (v.). Also see -oon.
1650s, from lampoon (n.), or else from French lamponner, from the Middle French noun. Related: Lampooned; lampooning.