bug
(scarecrow, hobgoblin), perhaps from obsolete Welsh (bwg) ("ghost, hobgoblin"; compare Welsh (bwgwl) ("threat", older "fear")) or from (swollen up, thick), from (*bʰew-), (to swell) (compare (big man), dialectal Low German (goblin”, “snot)). Or, from a word related to (buck) and originally referring to a goat-shaped spectre.
(beetle), from (budda) (see (dung beetle)), from (*buddô), (*buzdô), from the same ultimate source as above (compare (louse, grub), (newborn domestic animal)). More at (bud).
(entomology) An insect of the order (order) (the “true bugs”).
Any of various species of marine or freshwater crustaceans; e.g. a Moreton Bay bug, mudbug.
(informal) Any insect, arachnid, or other terrestrial arthropod that is a pest.
(informal) Any minibeast.
(US) Any insect, arachnid, myriapod or entognath.
(specifically) A bedbug.
A contagious illness, or a pathogen causing it.
(informal) An enthusiasm for something; an obsession.
(informal) A keen enthusiast or hobbyist.
A concealed electronic eavesdropping or intercept device.
A small and usually invisible file (traditionally a single-pixel image) on a World Wide Web page, primarily used to track users.
(Maine) A lobster.
(broadcasting) A small, usually transparent or translucent image placed in a corner of a television program to identify the broadcasting network or cable channel.
(aviation) A manually positioned marker in flight instruments.
A semi-automated telegraph key.
(obsolete) Hobgoblin, scarecrow; anything that terrifies.
("the bug") HIV.
(poker) A limited form of wild card in some variants of poker.
(slang) A trilobite.
(dated) (oil bug).
(horse-racing) An asterisk denoting an apprentice jockey's weight allowance.
(by extension) A young apprentice jockey.
(printing) (union bug).
(slang) A small piece of metal used in a slot machine to block certain winning combinations.
(slang) A metal clip attached to the underside of a table, etc. to hold hidden cards, as a form of cheating.
(annoy) To annoy.
(be creepy) To act suspiciously or irrationally, especially in a way that annoys others.
(surveil, audially) To install an electronic listening device or devices in.
(of eyes) To bulge or protrude.