Here are examples of the word/phrase "inscrutable" used in a sentence and paraphrased in a sentence...
I was sent an inscrutable message relating to my future.
I was sent a mysterious message relating to my future.
The professor came up with an inscrutable equation to solve this difficult problem.
The professor concocted a cryptic equation to solve this difficult problem.
The wise owl's clue for what I should do next was somewhat inscrutable.
The wise owl's clue for what I should do next was somewhat abstruse.
Other Examples...