Bugaboo

Bug·a·boo

Bugaboo

n.
  1. Something frightful, as a specter; anything imaginary that causes needless fright; something used to excite needless fear; also, something really dangerous, or an imaginary monster, used to frighten children, etc.
    But, to the world no bugbear is so great As want of figure and a small estate.
    The bugaboo of the liberals is the church pray.
    — S. B. Griffin.
    The great bugaboo of the birds is the owl.
    — J. Burroughs.
  2. a source of concern; as, the old bugaboo of inflation still bothers them.