From Longman Dictionary of Contemporary Englishenigmae‧nig‧ma /ɪˈnɪɡmə/ noun [countable] MYSTERIOUSsomeone or something that is strange and difficult to understand SYN mystery The neighbours regarded him as something of an enigma.
Examples from the Corpus
enigma• But despite all the efforts to make sense of the artist, he remains elusive, an enigma.• He was to a certain extent an enigma.• Madeleine was still very much an enigma to him.• It is something of an enigma how a man who could not bear to hurt a living thing could serve as defence secretary.• Louisiana, though penetrated, remained an enigma.• Lorraine remains an enigma who is easy to admire but impossible to get to know.• It is as baffling a production enigma as anything in Maclean's own life.• It is more like something surgical - the unpleasant shape of stumpy enigmas.• As I studied more about their past, I became more puzzled, and the enigma expanded.Origin enigma (1500-1600) Latin aenigma, from Greek, from ainos “story” 