I take mundane to mean anything and everything that can be taught in language. Supramundane is experiential understanding, that which is seen directly by investigation and observation, not itself based on thought. Supramundane understanding is like knowing what sight is by seeing, or what sound is by hearing; it's not the sights and sounds themselves, separated and classified conceptually, but rather the experience itself. Enough of these experiences intuitively re-direct the mind and transform the mind until wrong views are abandoned.