すみません (かん)
すみません (かん) · sumimasen (kan) · JLPT N3 · noun
sorry
🙇 From sumu, to be settled: sumimasen = it isn't settled, I still owe you
The verb 済む (sumu) means to be finished or settled. Sumimasen is its negative, so it literally says this is not settled. You use it when you owe someone, whether for a mistake, a favour, or taking up their time.