famhair

a giant, Irish fomhor, pirate, giant, Early Irish fomór, fomórach, a Fomorian, a mythic race of invaders of Ireland; *fo-mór, "sub-magnus" (Zimmer). Stokes refers the -mor, -morach, to the same origin as mare of nightmare, German mahr, nightmare. Rhys interprets the name as "sub-marini", taking mor from the root of muir, sea. The ó of mór, if it is long (for it is rarely so marked) is against these last two derivations.