Origin of henchman
- Middle English hengsman, henshman servant to a person of rank hengest horse (from Old English) man man man
From American Heritage Dictionary of the English Language, 5th Edition
- From Middle English hencheman, henseman, henxman (“a groom, page, attendant”), from Old English *hengstmann, *hengestmann (“groom”, literally “horseman”), from hengst, hengest (“stallion, horse, steed, gelding”) (from Proto-Germanic *hangistaz (“stallion”), from Proto-Indo-European *ḱanḱest-, *kankest- (“horse”)) + mann (“man”). Cognate with German Hengstmann (“a groom”), Icelandic hestamaður (“horseman, groom”). More at man.