adjective
also um·teenth -ēn(t)th
: being the latest or last in an indefinitely numerous series
postponed for the umpteenth time — Time
made the umpteenth mistake that day
adjective
also um·teenth -ēn(t)th
: being the latest or last in an indefinitely numerous series
postponed for the umpteenth time — Time
made the umpteenth mistake that day
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012