adj. That cannot be apprehended; not apprehensible to or graspable by either body or mind.
the GNU version of the Collaborative International Dictionary of English
adj. Not apprehensible; unintelligible; inconceivable.
The Century Dictionary and Cyclopedia
Not apprehensible or intelligible.
Word Usage
"In the swirl of the Libby affair, one loses sight of the real offense, and it becomes almost inapprehensible what it is that Cheney/Libby/Rove got themselves into."