one of the three sons of Usnach, great warrior who lived in Conchobar’s train. Deirdre fell in love with him. After the " geis " she put on him, he had to flee with her, far away from Conchobar’s anger. He was killed by Eogan.

In Irish mythology, Naoise (also spelled Noisiu) was the nephew of King Conchobar of Ulster, and a son of Usnech (or Uisliu), in the Ulster Cycle.