/ Dictionary / Index M monkey business: Meaning and Definition of Find definitions for: mon'key busi"ness Pronunciation: [key] frivolous or mischievous behavior. improper or underhanded conduct; trickery. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. monkey bridge monkey dog Related Content Daily Word Quiz: punctual Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language