I had always assumed it was Kame-hame-ha—is it, then, Ka-meha-meha? *wikipedia* ah, the article on Kamehameha the Great says that
Paiʻea is said to have had a dour disposition, and acquired the name he is best known for today: Ka mehameha, from the Hawaiian language for "the lonely one".
Huh. Learn something new every day!