/ Dictionary / Index U undercover: Meaning and Definition of Find definitions for: un•der•cov•er Pronunciation: (un"dur-kuv'ur, un'dur-kuv"-), [key] — adj. working or done out of public sight; secret: an undercover investigation. engaged in spying or securing confidential information: an undercover agent. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: undercover (Thesaurus) undercount undercroft Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language