inconceivable

Impossible to comprehend or grasp fully.

So unlikely or surprising as to have been thought impossible; unbelievable.

Incapable of being conceived, or realized in the imagination; incredible; inexplicable.

An expression which conveys no conception whatever, but is mere gibberish, is not called inconceivable, but unintelligible. The word inconceivable (see also unconceivable) is used in the following senses in philosophy: Involving a contradiction in terms, such as the idea of a non-existent being.

Unacceptable to the mind because involving a violation of laws believed to be well established by positive evidence, as a perpetual motion.