run amuck
One of the few Malaysian words to have entered the English language. It originally meant to enter into a murderous rage, and go running around killing people indiscriminately. These days it just means to act wild or crazy. It is almost always used in the phrase 'to run amok'.
The word was first picked up by Portuguese explorers, who wrote it as amouco or amuco. The phenomenon of running amok was interesting enough that it soon made it into English stories of far-away lands, although the proper spelling was very much a matter of opinion.
Here are the earliest known appearances of Amok in the English language:
In 1663 Cogan wrote in Pinto's Travels {of the far east}: "All those which were able to bear arms should make themselves Amoucos , that is to say, men resolved either to dye, or vanquish."
In 1672, Marvell wrote : "Like a raging Indian... he runs a mucke (as they cal it there) stabbing every man he meets."
In 1772, Captain James Cook explained: "Jealousy of the women is the usual reason of these poor creatures {Malayians} running amock."