/ Dictionary / Index U umpteenth: Meaning and Definition of Find definitions for: ump•teenth Pronunciation: (ump'tēnth'), [key] — adj. Informal. of an indefinitely large number in succession: He was the umpteenth person to arrive. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: umpteenth (Thesaurus) umpteen umpty-umpth Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language