e·nig·ma 
(ĭ-nĭgmə)
(ĭ-nĭgmə)n. pl. e·nig·mas also e·nig·ma·ta (-mə-tə)
1. One that is puzzling, ambiguous, or inexplicable.
2. A perplexing speech or text; a riddle.
[Latin aenigma, from Greek ainigma, from ainissesthai, ainig-, to speak in riddles, from ainos, fable.]