/ Dictionary / Index M mostest: Meaning and Definition of Find definitions for: most•est Pronunciation: (mōs'tist), [key] — adj., n. Slang. most. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mostest (Thesaurus) most most-favored-nation Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language