fir·bolg \ˈfi(ə)rˌbələg\noun plural orfir·bolgs\-gz\ Usage: usually capitalized Etymology: Old Irish fir Bolg men of the Builg (a Celtic people), from fir (plural of fer man) + Bolg, gen. plural of Builg; akin to Welsh gwr man, Breton gour, Latin vir — more at virile : an early people of Ireland