I used a Hint power and didn't get a hint, or didn't get the best hint (AB2)

This is a known behavior that unfortunately we won't be fixing in the foreseeable future. Alphabear 2 has multiple dictionaries, including some that provide word definitions (but let's pretend that they all comprise a single Definitions Dictionary) and one that determines whether a word is acceptable. The words in these dictionaries are not identical; there are some acceptable words for which we don't have definitions, and some unacceptable words for which we do have definitions. Unfortunately, for technical reasons we have to give certain kinds of hints with the Definitions Dictionary, even though (were it possible) we'd want to give them from the Acceptability Dictionary instead. So there may be cases where there is an acceptable word on the board, and yet the Hint power won't be able to give it to you as a hint because it doesn't also occur in the Definitions Dictionary. But don't worry; if you see an acceptable word, you can play it even if the game won't give it to you as a Hint.