bug

Origin: First attested in this form around 1620 (referring to a “bedbug”), from earlier beetle, from which is traced alternatively to: * a Celtic root found in and obsolete ; compare Welsh threat, fear and . * , from , to swell; compare , dialectal Low German goblin, snot. * or to a word related to buck and originally referring to a goat-shaped spectre. For the “insect” meaning the assonance with , from , from , *buzdô, from the same ultimate source as above, might have played a role. Compare , . More at bud. But ultimately this convergence of meaning doesn't prove a conflation of the two terms; th. Origin information sourced from Wiktionary contributors (CC BY-SA 4.0).