What a complicated word this is – “ineffable.” If something has a quality that is ineffable, it is not possible to express it in words. Often, this is because the quality is too beautiful, too grand, too exalted.
One set of metaphors we found in our Adult Ed class was those attempts to describe something that was indescribable. (Put aside the fact that calling something indescribable is, in fact, describing it.) God is Alone, the Eternal, the Answer to all of the “why” questions. We know the letters of God’s name, but not how to actually say them out loud.