The definition of the adjective “enigmatic” is “of, relating to, or resembling an enigma,” but that’s not very useful if you don’t understand what an enigma is. There are a few meanings, but the broadest is “something hard to explain or understand.” “Enigma” is also often used to refer specifically to a mysterious person. You might say, “The woman who moved in down the street seems like an enigma.” Finally, “enigma” is sometimes used to refer to an especially obscure speech or piece of writing. A philosopher might study enigmas related to a specific topic. Any of these contexts could be described as “enigmatic.” Both the adjective and noun forms come from the Greek “ainissesthai,” meaning “to speak in riddles,” and “ainos,” meaning “fable.”