the word 'swarthy' entered modern english from the late middle english 'swarty', an alteration of the earlier 'swarty'. this, in turn, evolved from the old english 'sweart', meaning 'black' or 'dark'. the old english term traces its lineage back to the proto-germanic 'swarta-', and ultimately to the proto-indo-european root 'swerd-', meaning 'dirty, dark, black'. the semantic journey is direct, moving from the general concept of darkness to its specific application in describing a dark or dusky complexion.

the word is a simplex form derived from a single root.