/ Dictionary / Index T thwack: Meaning and Definition of Find definitions for: thwack Pronunciation: (thwak), [key] — v.t. to strike or beat vigorously with something flat; whack. —n. a sharp blow with something flat. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: thwack (Thesaurus) thuya thwart Related Content Daily Word Quiz: sumptuous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language