1560s, "wild, unruly" (originally in reference to hawks), from French haggard, probably from Old French faulcon hagard "wild falcon," literally "falcon of the woods," from hagard, hagart, from Middle High German hag "hedge, copse, wood," from Proto-Germanic *hagon, from PIE root *kagh- "to catch, seize;" also "wickerwork, fence" (see hedge (n.)). OED, however, finds this derivation "very doubtful." Sense perhaps reinforced by Low German hager "gaunt, haggard." Sense of "with a haunted and wild expression" first recorded 1690s; that of "careworn" first recorded 1853. Sense influenced by association with hag. Related: Haggardly; haggardness.
dish of chopped entrails, c. 1400, now chiefly Scottish, but it was common throughout England to c. 1700, of uncertain origin. Perhaps from Old French hacheiz "minced meat," from agace "magpie," on analogy of the odds and ends the bird collects. The other theory [Klein, Watkins, The Middle English Compendium] traces it to Old English haggen "to chop," or directly from Old Norse höggva "to hew, cut, strike, smite" (see hack (v.1)).
1680s, "ridden by hags or witches," past-participle adjective from hag-ride (1660s); see hag (n.) + ridden. From 1702 as "oppressed, harassed;" 1758 as "afflicted by nightmares." An old term for sleep paralysis (the sensation of being held immobile in bed, often by a heavy weight, and accompanied by a sense of alien presence). A holed stone hung over the bed was said to prevent it.