Since it is distinguished from the ordinary conceptual mind, then it cannot be defined through the ordinary conceptual mind.
What you are trying to express or define is beyond duality ie. does not have an opposite. It is beyond existence or nonexistence. Beyond self and non-self. Beyond recognition and discognition, beyond time (ever or never), beyond purity/clarity or pollution. Etc. etc. There is no word in any language to describe it.
Those who have no perception of it will not understand no matter which words are used and those who have experience of it can understand each other without any words or definitions.