/ Thesaurus / L Synonyms of little sioux river Find synonyms for: Noun1. Little Sioux Riverusage: a river that rises in southwestern Minnesota and flows southwestward to the Missouri River in western IowaWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language