Definition & Meaning of "not (even) know the meaning of the word"in English

What is the origin of the idiom "not know the meaning of the word" and when to use it?

This idiom "not know the meaning of the word "likely stems from the idea that when someone is completely unfamiliar with a concept or word, it might as well be in a foreign language or dialect. This expression is used when people want to highlight that someone is so unfamiliar with a topic that they cannot even comprehend basic terms associated with it.