Des MoinesyoudaoicibaDictYouDict[Des Moines 词源字典]
city in Iowa, U.S., named for French Rivière des Moines, the river that flows past it, which traditionally is derived from French des moines "of the monks," in reference to missionaries, but this probably is a fur trappers' folk-etymologizing of a name of the native people who lived there.

The place appears in a 1673 text as Moinguena, and historians believe this represents Miami-Illinois mooyiinkweena, literally "shitface," from mooy "excrement" + iinkwee "face;" a name given by the Peoria Indians (whose name has itself become a sort of insult) to their western neighbors. It is not unusual for Indian peoples to have hostile or derogatory names for others, but this seems an extreme case.[Des Moines etymology, Des Moines origin, 英语词源]