/ Dictionary / Index K knee-slapper: Meaning and Definition of Find definitions for: knee-slap•per Pronunciation: (nē'slap"ur), [key] — n. Informal. a joke evoking boisterous hilarity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. kneesies knee-socks Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language