Something frightful, as a specter; anything imaginary that causes needless fright; something used to excite needless fear; also, something really dangerous, used to frighten children, etc
Something or someone that is your bugbear worries or upsets you. Money is my biggest bugbear. something that makes people feel annoyed or worried (Probably from bug ( BUG) + BEAR1)
an object of dread or apprehension; "Germany was always a bugbear for France"; "A foolish consistency is the hobgoblin of little minds"--Ralph Waldo Emerson