n. 1 a small shell-less mollusc of the class Gastropoda often destructive to plants. 2 a a bullet esp. of irregular shape. b a missile for an airgun. 3 Printing a a metal bar used in spacing. b a line of type in Linotype printing. 4 esp. US a tot of liquor. 5 a unit of mass, given an acceleration of 1 foot per second per second by a force of 1 lb. 6 a roundish lump of metal.
[ ME slugg(e) sluggard, prob. f. Scand. ]