Bugbear
WordNet
noun
(1) 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
(2) An imaginary monster used to frighten children
WiktionaryText
Noun
- An ongoing problem; a recurring obstacle or adversity.
- A source of dread; resentment; or irritation.
- An imaginary creature meant to inspire fear in children.