D defs.my
Entry 1 sense Webster, 1913

Bluebeard

/blo͞ob'-ērdˌ/ · Blue·beard · IPA /blˈuːbˌiːrd/
01 n. The hero of a mediæval French nursery legend, who, leaving home, enjoined his young wife not to open a certain room in his castle. She ente…
  1. 1.
    The hero of a mediæval French nursery legend, who, leaving home, enjoined his young wife not to open a certain room in his castle. She entered it, and found the murdered bodies of his former wives. -- Also used adjectively of a subject which it is forbidden to investigate.
    “The Bluebeard chamber of his mind, into which no eye but his own must look.” Carlyle.