1 : of an obscure nature; "the new insurance policy is written without cryptic or mysterious terms"; "a deep dark secret"; "the inscrutable workings of Providence"; "in its mysterious past it encompasses all the dim origins of life"- Rachel Carson; "rituals totally mystifying to visitors from other lands"
2 : suggesting the operation of supernatural influences; "an eldritch screech"; "the three weird sisters"; "stumps...had uncanny shapes as of monstrous creatures"- John Galsworthy; "an unearthly light"; "he could hear the unearthly scream of some curlew piercing the din"- Henry Kingsley