/ Dictionary / Index M motor-mouth: Meaning and Definition of Find definitions for: mo•tor-mouth Pronunciation: (mō'tur-mouth"), [key] — pl. -mouths a person who is a constant or irrepressible talker. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: motor-mouth (Thesaurus) motor-minded motor neuron Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language