/ Dictionary / Index U unpin: Meaning and Definition of Find definitions for: un•pin Pronunciation: (un-pin'), [key] — -pinned, -pin•ning. to remove pins from. to unfasten or loosen by or as if by removing a pin; detach. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: unpin (Thesaurus) unpile unplait Related Content Daily Word Quiz: crutiny Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language