A little hyperbole never hurt anyone. Certainly, "for the millionth time" is often used, in a hyperbolic sense, when one is exasperated at having to repeat something to someone who wasn't listening the first 999 thousand times.

How do you use millionth in a sentence?

In 1955 the millionth ton of the coal was produced. Atlas also raised its one millionth dollar as an organization in 2011. A clock with an accuracy of one in a million will introduce an error of one millionth of a second each second. He sold his millionth book in 1996 and his two-millionth in 2005.

Is it millionth or million?

The millionth item in a series is the one you count as number one million. Last year the millionth truck rolled off the assembly line. A millionth of something is one of a million equal parts of it.