/ Dictionary / Index U underprop: Meaning and Definition of Find definitions for: un•der•prop Pronunciation: (un"dur-prop'), [key] — -propped, -prop•ping. to prop underneath; support; uphold. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. underproof underquote 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