/ Dictionary / Index T toughen: Meaning and Definition of Find definitions for: tough•en Pronunciation: (tuf'un), [key] — v.t., v.i. to make or become tough or tougher. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: toughen (Thesaurus) tough toughie Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language