Definition of slug

• n. - A drone; a slow, lazy fellow; a sluggard.
• n. - A hindrance; an obstruction.
• n. - Any one of numerous species of terrestrial pulmonate mollusks belonging to Limax and several related genera, in which the shell is either small and concealed in the mantle, or altogether wanting. They are closely allied to the land snails.
• n. - Any smooth, soft larva of a sawfly or moth which creeps like a mollusk; as, the pear slug; rose slug.
• n. - A ship that sails slowly.
• n. - An irregularly shaped piece of metal, used as a missile for a gun.
• n. - A thick strip of metal less than type high, and as long as the width of a column or a page, -- used in spacing out pages and to separate display lines, etc.
• v. i. - To move slowly; to lie idle.
• v. t. - To make sluggish.
• v. t. - To load with a slug or slugs; as, to slug a gun.
• v. t. - To strike heavily.
• v. i. - To become reduced in diameter, or changed in shape, by passing from a larger to a smaller part of the bore of the barrel; -- said of a bullet when fired from a gun, pistol, or other firearm.