Hello! These words have opposite meanings: Scrutable: something that can be deciphered or understood Unintelligible: something that CAN'T be deciphered or understood Both words are pretty formal and they would be used in literary or academic texts. In a normal conversation you would say "understandable" instead of "scrutable" and "difficult to understand" or "confusing" instead of "unintelligible". I hope to have helped you!