noun, plural Fir·bolgs, (especially collectively) Fir·bolg. Irish Legend.
Examples from the Web for firbolgs
The Firbolgs, a rude people, held Ireland for a long period.Thomas Davis, Selections from his Prose and Poetry|Thomas Davis
And on the fourth day the Men of Dea got the upper hand, and the Firbolgs were driven back.Gods and Fighting Men|Lady I. A. Gregory
The Firbolgs had scarcely established themselves in the island when a fresh set of invaders appeared on the scene.
This third body of invaders is known collectively as Firbolgs, and is ethnologically and historically very important.
Next came Nemed and his people; and after these the Firbolgs, who were conquered and succeeded by the Dedannans.Old Celtic Romances|Unknown
1797, ancient supernatural people of Ireland (enemies of the Dannans), perhaps from Old Irish fir, plural of fear "man" + bolg, genitive plural of bolg "bag, belly;" or second element may be cognate with Gaulish Belgae.