Pronunciation: (in-skrOO'tu-bul), [key]
1. incapable of being investigated, analyzed, or scrutinized; impenetrable.
2. not easily understood; mysterious; unfathomable: an inscrutable smile.
3. incapable of being seen through physically; physically impenetrable: the inscrutable depths of the ocean.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.