Bugaboo (The Flea)
WordNet
noun
(1) A source of concern
"The old bugaboo of inflation still bothers them"
(2) An imaginary monster used to frighten children
WiktionaryText
Noun
- An imagined fear or threat, or a fear presumed larger than it really is.
- 1949 - George R. Stewart Earth Abides, p. 80
- ...a fear had come upon them, and they had a kind of bug-a-boo terror about roving gangsters.