Haggis
late Middle English: probably from earlier hag ‘hack, hew’, from Old Norse hǫggva .
wiktionary
From Late Middle English hagis(“haggis”), from hag, haggen(“to chop, cut, hack; to cut into”) (from Old Norse hǫggva(“to hew”)), [1] or from hakken(“to chop, hack; to dice, mince”) (from Old English hēawan(“to chop, hew; to dice, mince”)), [2] both ultimately from Proto-Indo-European *kewh₂-(“to hew; to beat, strike; to forge”). [3]
haggi + -s.
etymonline
haggis (n.)
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)).