naithir
Definitions (by source)
a serpent. npl. nathracha (so IGT), 4742; nathruigh, 4726; naithre, 5543.
Leabhar Branach: The Book of the O'Byrnes. Editor: Seán Mac Airt.
a snake, 1025.
Poems on the O'Reillys. Editor: James Carney.