noun
- any of a large number of small, gastropod mollusks, esp. the ones resembling a land snail, but having only a rudimentary internal shell buried in the mantle
- a smooth, soft moth (family Eucleidae) or sawfly larva, resembling a slug
- a person, vehicle, etc. that moves sluggishly
Origin:
ME slugge, slow, clumsy person or thing < Scand, as in Swed dial. slogga, to be sluggish < IE base *(s)leu-, to hang loosely, lax > sludge