any source, real or imaginary, of needless fright or fear.

a persistent problem or source of annoyance.

Folklore . a goblin that eats up naughty children.

noun

abhorrence , abomination , anathema , aversion , bte noire , detestation , execration , apprehension , bogey , bogy , boogeyman , bugaboo , dread , fear , ghost , goblin , gremlin , hobgoblin , loup-garou , ogre , problem , scare , specter , terror , threat , wraith