indigenous people of Guam and the Marianas Islands, 1905, from Spanish Chamorro, literally "shorn, shaven, bald." Supposedly because the men shaved their heads, but the name also has been connected to native Chamoru, said to mean "noble," so perhaps Chamorro is a Spanish folk-etymology.
CHAMORRO a scornful name, given by the Spaniards to the Portuguese, who used to cut off the hair. From the Spanish Chamorro, bald [Anthony Vierya Transtagano, "Dictionary of the Portuguese and English Languages," London, 1773]