Learned the word for “late” in my Vietnamese class yesterday. In fact, there are two words: muộn (Nth VN) and trễ (Sth VN).
To be late = đến muộn/trễ
e.g. Tôi có thể sẽ đến muộn tuần sau. (I could be late [to class] next week.)
Geek note: muộn is probably an early borrowing of 晚 from Chinese (cf muôn 萬/万)