1. A bugbear; anything which terrifies. Sir, spare your threats: The bug which you would fright me with i seek. (Shak)
According to present popular usage in England, and among housekeepers in America, bug, when not joined with some qualifying word, is used specifically for bedbug. As a general term it is used very loosely in America, and was formerly used still more loosely in England. God's rare workmanship in the ant, the poorest bug that creeps. . This bug with gilded wings. . Bait bug. See bait. Bug word, swaggering or threatening language.