/ Dictionary / Index T thickheaded: Meaning and Definition of Find definitions for: thick•head•ed Pronunciation: (thik'hed"id), [key] — adj. (of a person) dull-witted; stupid. (of an animal) having a thick head. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: thickheaded (Thesaurus) thickhead thick-knee Related Content Daily Word Quiz: ravenous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language