Firbolgs (n.)youdaoicibaDictYouDict[Firbolgs 词源字典]
1797, ancient supernatural people of Ireland (enemies of the Dannans); according to OED perhaps from Old Irish fir, plural of fear "man" + bolg, genitive plural of bolg "bag, belly;" or the second element may be cognate with Gaulish Belgae. Related: Firbolgian.[Firbolgs etymology, Firbolgs origin, 英语词源]