1. being an indefinitely large number in a sequence; countless
Usage: informal

Examples

• This is the umpteenth time I’ve told you to clean your room.
• She checked her phone for the umpteenth time that morning.
• After his umpteenth attempt, he finally solved the puzzle.
• The teacher gave her umpteenth warning about talking in class.
• I’ve heard that joke for the umpteenth time today.
• This is my umpteenth cup of coffee this week.