Ilunga
Etymology
From Tshiluba, a language of the Democratic Republic of the Congo. In 2004 it topped a poll of professional translators as the world’s "most untranslatable word," which is how it reached English; however, native speakers and linguists have since disputed both that ranking and the tidy three-strikes definition, so it is best cited with that caveat.
noun · /ee-LOON-gah/
A person who is willing to forgive a wrong the first time, tolerate it the second, but never a third.
What it names
A precise moral threshold for patience — exactly where forbearance runs out — that English needs a whole sentence to describe.
Example
My grandfather had a real ilunga about him — endlessly patient, until the day he simply wasn’t.
Related idea
It is a more finely calibrated cousin of forbearance, pinning tolerance to a specific count of offenses, though its fame owes as much to a translators’ poll as to everyday use.