I have been looking at the kanji in level 47. The kanji 崖 is introduced in this level, with the onyomi がい. In the vocabulary the onyomi is not used for any word. The kunyomi がけ is taught there.
Could I suggest a vocabulary word using the onyomi? 断崖 (だんがい)、”cliff". It happens to be the Japanese title of the famous Hitchcock movie Suspicion