IPA: /ˈoʊvərˌduː/
KK: /ˈoʊvərˌdu/
Something that should have happened or been paid earlier than it actually is.
The library charged me a fee for my overdue book.
Overdue → It is formed from "over-" (meaning excessively or beyond) and "due" (from Latin "debere", meaning to owe). The word "overdue" means something that is excessively owed or has not been paid or completed by the expected time.
Think of something that is 'beyond' ('over-') the time it was 'owed' ('due') — that's why overdue means it should have been done or paid by now.