/ Dictionary / Index B Big Muddy: Meaning and Definition of Find definitions for: Big' Mud'dy Pronunciation: [key] a nickname of the Missouri River. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. bigmouthed Big Muddy River Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language