Emily Dickinson Lexicon

MOTH, n. [Sax. mogthe, mohth, moth, or matha; Goth. matha; D. mot; G. motte.]

1. An animal of the genus Phalæna, which breeds in yarn and garments, and often does injury by eating the substance and destroying the texture. Matth. vi. The name is also applied to the whole genus.
2. Figuratively, that which gradually and silently eats, consumes or wastes any thing. Idle persons are a moth to the community.