slug

\ \ English has at least two, possibly four distinct words slug. The oldest, ‘shell-less mollusc’ [15], originally meant ‘slow or lazy person’. It was not applied to the slow-moving animal until the 18th century. It was probably a borrowing from a Scandinavian source (Norwegian has a dialectal slugg ‘large heavy body’). A similar ancestor, such as Swedish dialect slogga ‘be lazy’, may lie behind the now obsolete English verb slug ‘be lazy’, from which were derived sluggard [14] and sluggish [14]. Slug ‘bullet’ [17] is of uncertain origin. It may have come from slug ‘mollusc’, in allusion to the shape of the animal, but that suggestion depends on the supposition that slug was being used for the mollusc at least a hundred years before our earliest written record of it. Slug ‘swig of drink’ [18] may be the same word, but it has also been speculated that it comes from Irish Gaelic slog ‘swallow’. Slug ‘hit’ [19] and the related slog [19] probably go back ultimately to the prehistoric Germanic base *slakh-, *slag-, *slōg- ‘hit’ (source of English slaughter, slay, etc).

\ \ Cf.⇒ SLOG