Bunion

google

ref

early 18th century: ultimately from Old French buignon, from buigne ‘bump on the head’.

wiktionary

ref

From alteration of earlier bunny(“lump, swelling”), from Middle English bony, boni(“bunion, swelling”), perhaps Italian bubbone (augmented form of bugno(“beehive”)), or more likely from Lombard bugnon(“bunyon”), all three from Old French bugne, buigne, bune(“bump, knob, swelling”), from Old Norse bunga(“an elevation, bulge”) or Frankish *bungjo(“a swelling, lump, bump”), both from Proto-Germanic *bungô, *bunkô(“lump, clump, heap, crowd”), from Proto-Indo-European *bʰenǵʰ-(“thick, dense, fat”). Cognate with Dutch bonk(“lump, clump”), German Bunge(“swelling, tuber”).

etymonline

ref

bunion (n.)

"swelling on the foot caused by inflammation of a bursa," 1718, apparently from East Anglian dialectic bunny "lump, swelling" (16c.), which is probably from French buigne "bump on the head, swelling from a blow" (see bun).