These two words together mean especially nothing. It would be abraded to give a real meaning. It would be more appropriate separate the two terms, transcribe their meanings separately, and then join them. You would get something like "the opposite to an undisputed truth", which would not be the same as saying 'a questionable truth', but it is intended that an "antonym", or an "opposite", was indisputable. Axiom is any statement that does not need to be demonstrated. I.e. a clear saying to everyone: "light, illuminating." And an "antonym" is a name with meaning instead of another. ("easy" is the antonym of 'difficult'; and, conversely, "hard" is the antonym of 'easy'. Say "antonym axiom", doesn't mean anything without knowing what term is "antonym", as a term of reference, you need another word which is the contradiction. If there is no tree, "his reflection" in the water, not you can see although there is water. You could say that expression as Baroque and improperly educated, can be seen as nonsense, though its meaning may be given.
