Arabic also has an apparently bottomless well of vocabulary in addition to having few cognates, and that vocabulary varies depending on whether you are reading a newspaper or listening to a sitcom. Don’t assume a word is too rare or strange, and you’re never going to see it again. For it, make a flashcard. It will be back, even if only as a joke among fellow students, to work it into your repertoire. (Sab’a, to put his finger in a hen, really?!)