Etymology
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inscrutable (adj.)
"that cannot be discovered by searching, mysterious," c. 1500, from Late Latin inscrutabilis, from in- "not, opposite of" (see in- (1)) + *scrutabilis, from scrutari "examine, ransack" (see scrutiny). Related: Inscrutably; inscrutableness.
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scrutable (adj.)
c. 1600, probably a back-formation from inscrutable.
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