loco (adj.)youdaoicibaDictYouDict[loco 词源字典]
1844, American English, from Spanish loco (adj.) "insane," of uncertain origin, perhaps from Arabic lauqa, fem. of 'alwaq "fool, crazy person." Loco-weed (1877) was name given to species of western U.S. plants that cause cattle and horse diseases that make them stagger and act strangely.[loco etymology, loco origin, 英语词源]