Mysterious means that which is difficult to understand. This word can be used to describe something, someone or a place that is characterised by strangeness and secrecy. Mysterious is a synonym to enigmatic and cryptic.
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what does mysterious mean
full of, characterized by, or involving mystery: a mysterious occurrence.
implying or suggesting a mystery: a mysterious smile.
of obscure nature, meaning, origin, etc.; puzzling; inexplicable: a mysterious inscription on the ancient tomb.