Emily Dickinson Lexicon

BUG, or BUG'BEAR, n. [W. bwg, a hobgoblin or scarecrow; bugadu, to terrify; Russ. buka, a sprite or goblin. In Pers. بَاكْ bauk, is fear.]

A frightful object; a walking specter; any thing imaginary that is considered as frightful. – Locke. Pope.