'umpteenth' definitions:

Definition of 'umpteenth'

(from WordNet)
adjective
Last in an indefinitely numerous series [syn: umpteenth, umteenth, umptieth]

Definition of 'umpteenth'

From: GCIDE
  • umpteenth \ump"teenth\, a. Ordinal of umpteen, with corresponding signification; as, for the umpteenth time, I'm telling you to stop. [Colloq.] [PJC]