amok: [17] Amok is Malayan in origin, where it is an adjective, amoq, meaning ‘fighting frenziedly’. Its first brief brush with English actually came in the early 16th century, via Portuguese, which had adopted it as a noun, amouco, signifying a ‘homicidally crazed Malay’. This sense persisted until the late 18th century, but by then the phrase run amok, with all its modern connotations, was well established, and has since taken over the field entirely. The spelling amuck has always been fairly common, reflecting the word’s pronunciation.
in verbal phrase run amok first recorded 1670s, from Malay amuk "attacking furiously." Earlier the word was used as a noun or adjective meaning "a frenzied Malay," originally in the Portuguese form amouco or amuco.
There are some of them [the Javanese] who ... go out into the streets, and kill as many persons as they meet. ... These are called Amuco. ["The Book of Duarte Barbosa: An Account of the Countries Bordering on the Indian Ocean and Their Inhabitants," c. 1516, English translation]
