SLUG

noun

1. Any of many terrestrial pulmonate gastropod mollusks, having no (or only a rudimentary) shell.
2. A slow, lazy person; a sluggard.
3. A bullet or other projectile fired from a firearm; in modern usage, generally refers to a shotgun slug.

verb

1. To drink quickly; to gulp; to down.
2. To take part in casual carpooling; to form ad hoc, informal carpools for commuting, essentially a variation of ride-share commuting and hitchhiking.
3. (of a bullet) To become reduced in diameter, or changed in shape, by passing from a larger to a smaller part of the bore of the barrel.