/ Dictionary / Index D decongestant: Meaning and Definition of Find definitions for: de•con•ges•tant Pronunciation: (dē"kun-jes'tunt), [key] — Pharm. Pharm. —adj. of or pertaining to a substance that relieves mucus congestion of the upper respiratory tract. —n. any such substance. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: decongestant (Thesaurus) decongest decongestive Related Content Daily Word Quiz: impetuous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language