An evildoer, especially in a story.
A social label became a moral judgment.
Latin
villa
‘country house, farm’
into Medieval Latin
Medieval Latin
villanus
‘farmhand’
into Old French
Old French
vilain
‘peasant, farmer, commoner, churl, yokel’
into Middle English
Middle English
vilein
‘base or low-born rustic’
became English
English
villain
‘character in a novel, play, etc. whose evil motives or actions help drive the plot’
Villanus referred to a worker attached to a country estate. Through French vilain, a class-based description became an insult. English eventually sharpened the insult into wickedness, and later applied it to the antagonist in a story.
Dictionary word history; the component and historical references below supply additional detail.
Historical forms, meanings, and context for the route described here.
Villa and villain share a history. The connection records old social prejudice, rather than anything inherently wicked about farm work.