/ Dictionary / Index U undersized: Meaning and Definition of Find definitions for: un•der•sized Pronunciation: (un'dur-sīzd'), [key] — adj. smaller than the usual or normal size. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: undersized (Thesaurus) undersize underskirt 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