/ Dictionary / Index U unmentionable: Meaning and Definition of Find definitions for: un•men•tion•a•ble Pronunciation: (un-men'shu-nu-bul), [key] — adj. not mentionable; inappropriate, unfit, or improper for mention, as in polite conversation; unspeakable. —n. something that is not to be mentioned: That subject was classed among the unmentionables. undergarments. (formerly) trousers or breeches. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: unmentionable (Thesaurus) unmeet unmerciful Related Content Daily Word Quiz: fidelity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language