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• bug
  bug

  noun

  a hemipterous insect.
• Bug
  Bug

  noun

  a river in E central Europe, rising in W Ukraine and forming part of the boundary between Poland and Ukraine, flowing NW to the Vistula River in Poland. 450 miles (725 km) long.

bug

¹ American  

[buhg] / bʌg /

noun

1. Also called hemipteron, true bug, hemipteran. a hemipterous insect.

2. (loosely) any insect or insectlike invertebrate.

3. Informal. any microorganism, especially a virus.

   He was laid up for a week by an intestinal bug.

4. Informal. a defect or imperfection, as in a mechanical device, computer program, or plan; glitch.

   The test flight discovered the bugs in the new plane.

5. Informal.

   1. a person who has a great enthusiasm for something; fan or hobbyist.

      My wife is a real adventure bug, so we had a pretty thrilling, action-packed holiday.

   2. a craze or obsession.

      He's got the sports-car bug.

6. Informal.

   1. a hidden microphone or other electronic eavesdropping device.

   2. any of various small mechanical or electrical gadgets, as one to influence a gambling device, give warning of an intruder, or indicate location.

7. a mark, as an asterisk, that indicates a particular item, level, etc.

8. Horse Racing. the five-pound weight allowance that can be claimed by an apprentice jockey.

9. a telegraph key that automatically transmits a series of dots when moved to one side and one dash when moved to the other.

10. Poker Slang. a joker that can be used only as an ace or as a wild card to fill a straight or a flush.

11. Printing. a label printed on certain matter to indicate that it was produced by a union shop.

12. any of various fishing plugs resembling an insect.

13. Chiefly British. a bedbug.

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verb (used with object)

Informal.

• bugs,
  present (3rd person singular)
• bugged,
  past participle,  past
• bugging
  present participle

1. to install a secret listening device in (a room, building, etc.) or on (a telephone or other device).

   The phone had been bugged.

2. to bother; annoy; pester.

   She's bugging him to get her into show business.

   Synonyms:

   bait, plague, harass, badger, nag

verb phrase

1. bug off to leave or depart, especially rapidly.

   I can't help you, so bug off.

2. bug out to flee in panic; show panic or alarm.

idioms

1. put a bug in someone's ear, to give someone a subtle suggestion; hint.

   We put a bug in his ear about a new gymnasium.

bug ² American  

[buhg] / bʌg /

noun

Obsolete.

1. a bogy; hobgoblin.

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Bug ³ American  

[buhg, book] / bʌg, buk /

noun

1. Also called Western Bug. a river in E central Europe, rising in W Ukraine and forming part of the boundary between Poland and Ukraine, flowing NW to the Vistula River in Poland. 450 miles (725 km) long.

2. Also called Southern Bug. a river in SW Ukraine flowing SE to the Dnieper estuary. About 530 miles (850 km) long.

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bug ¹ British  

/ bʌɡ /

verb

1. a past tense and past participle of big 2

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bug ² British  

/ bʌɡ /

noun

1. obsolete an evil spirit or spectre; hobgoblin

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Bug ³ British  

/ buk /

noun

1. Also called: Southern Bug. a river in E Europe, rising in W Ukraine and flowing southeast to the Dnieper estuary and the Black Sea. Length: 853 km (530 miles)

2. Also called: Western Bug. a river in E Europe, rising in SW Ukraine and flowing northwest to the River Vistula in Poland, forming part of the border between Poland and Ukraine. Length: 724 km (450 miles)

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bug ⁴ British  

/ bʌɡ /

noun

1. any insect of the order Hemiptera , esp any of the suborder Heteroptera , having piercing and sucking mouthparts specialized as a beak (rostrum) See also assassin bug bedbug chinch bug

2. any insect, such as the June bug or the Croton bug

3. informal

   1. a microorganism, esp a bacterium, that produces disease

   2. a disease, esp a stomach infection, caused by a microorganism

4. informal an obsessive idea, hobby, etc; craze (esp in the phrases get the bug, be bitten by the bug, the bug bites, etc)

5. informal a person having such a craze; enthusiast

6. informal (often plural) an error or fault, as in a machine or system, esp in a computer or computer program

7. informal a concealed microphone used for recording conversations, as in spying

8. (in poker) a joker used as an ace or wild card to complete a straight or flush

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verb

1. (tr) to irritate; bother

2. (tr) to conceal a microphone in (a room, etc)

3. (intr) (of eyes) to protrude

bug Scientific  

/ bŭg /

1. An insect belonging to the suborder Heteroptera.

2. See more at true bug

3. An insect, spider, or similar organism. Not in scientific use.

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bug Cultural  

1. A generic term that describes a malfunction of undetermined origin in a computer or other electronic device.

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bug More Idioms  

More idioms and phrases containing bug

• cute as a button (bug's ear)
• put a bug in someone's ear
• snug as a bug in a rug
• what's eating (bugging) you

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Usage

What is a basic definition of bug? The word bug is used loosely to mean an insect or creature that resembles an insect. Bug is also used to mean a glitch or imperfection, as in a computer program. Bug is used as a verb to mean to bother or annoy someone. Bug has many other uses as a noun and verb. The word bug is used as a catch-all term for small, creepy pests. In general usage, it is used interchangeably with the word insect to refer to things like ants, bees, beetles, and even spiders. Scientists, though, use the words bug and insect to mean slightly different things. Insect refers to organisms that belong to Insecta, a very large class of animals whose members have a three-part body, six legs, and usually two pairs of wings. Scientists use bug (or true bug) to refer to the members of the order Hemiptera, which is within the Insecta class. Hemiptera members include cicadas, aphids, and stink bugs.

• Used in a sentence: He sat in the tent to try and avoid the bugs outside. 

Bug is used informally to refer to glitches or defects, especially when discussing electronics.

• Used in a sentence: The company didn’t release the new laptop until it had fixed all of the bugs. 

As a verb, bug means to annoy or to bother someone.

• Used in a sentence: Tom was bugged by his son jumping up and down while begging for ice cream.

Discover More

The term originated in the 1940s when the examination of a large computer revealed that an actual insect had landed on one of the circuits, shorting it out and shutting the machine down.

Other Word Forms

Derived Forms

• unbugged
  adjective

Inflected Forms

Participles

• bugging
  present
• bugged
  past

Conjugated Forms

Present

• bug
  simple
• bugs
  simple
• have bugged
  perfect
• has bugged
  perfect
• am bugging
  progressive
• are bugging
  progressive
• is bugging
  progressive
• have been bugging
  perfect progressive
• has been bugging
  perfect progressive

Past

• bugged
  simple
• had bugged
  perfect
• was bugging
  progressive
• were bugging
  progressive
• had been bugging
  perfect progressive

Future

• will bug
  simple
• will have bugged
  perfect
• will be bugging
  progressive
• will have been bugging
  perfect progressive

Etymology

Origin of bug¹

First recorded in 1615–25; 1885–90 bug ¹ for def. 4; 1910–15 bug ¹ for def. 5a; 1915–20 bug ¹ for def. 14; 1945–50 bug ¹ for def. 15; earlier bugge “beetle,” apparently alteration of Middle English budde, Old English -budda “beetle”; the sense “leave” (in bug off ) is obscurely related to other senses and perhaps is of distinct origin

Origin of bug²

First recorded in 1350–1400; Middle English bugge “scarecrow, demon, hobgoblin”; further origin unknown

Explanation

A bug is an insect. You might refuse to go camping because of your intense dislike for bugs. Bug can also be a verb meaning "annoy." Most likely, bugs bug you. There are bugs you can see, like bees, and bugs that are much smaller, like viruses and bacteria. If you get one of these microscopic bugs, it means you're sick. You can also say, casually, "I've caught the model train bug — I'm hooked!" A microphone that's hidden in someone's home or telephone is also a bug, named after its small size. To bug someone means either to spy on them, or simply to bother them relentlessly.

Example Sentences

See Examples For:

bug Bug bugs bugged bugging

Max Verstappen and Lewis Hamilton likened the effects of a software bug that affected multiple cars before the Bahrain Grand Prix in Malaysia to a "Lego race".

From BBC ● Oct. 4, 2026

While studying management to help his family's textile business, he attended an aviation seminar and caught what he later called the "aviation bug".

From Barron's ● Oct. 1, 2026

The bug is her “totally humorous take on hybridity.”

From Los Angeles Times ● Sep. 25, 2026

The team developed an AI-based controller that allows the robotic bug to perform demanding aerial maneuvers, including repeated body flips.

From Science Daily ● Sep. 22, 2026

They were like bug eyes, except they were a little square.

From "The Line Tender" by Kate Allen

First, on the day of the crime, she told police that two white men with long hair and similar builds got out of a car, a purple and pink Volkswagen Bug, and entered Black’s garage.

From Slate ● Feb. 13, 2026

Siegrist pounced, handing over his father’s old Ford Falcon and $2,278.54 for the Bug.

From The Wall Street Journal ● Nov. 30, 2025

The gamble paid off, with songs like Favourite and Bug ringing out around stadiums this summer – marking out Fontaines as the biggest guitar band of the 2020s.

From BBC ● Sep. 10, 2025

Piloting an e-scooter is the shirtless, much-tatted Bug, played by Barry Keoghan, last seen in “Saltburn” wearing significantly less.

From Los Angeles Times ● May 19, 2024

Doo-Doo Bug said, “You don’t have to leave, Miss Thomas.”

From "Bud, Not Buddy" by Christopher Paul Curtis

While vast clouds of flying bugs might not be everyone's cup of tea, scientists have been delighted to find that the Bogongs are back.

From Barron's ● Oct. 2, 2026

Bats are invaluable in agriculture, gorging on pests that target crops — corn earworms, brown stink bugs, cucumber beetles and more.

From Los Angeles Times ● Oct. 1, 2026

It said it has now patched the software bugs responsible for the mistakes.

From BBC ● Sep. 22, 2026

“It was pretty much just fight bugs, fight reptiles,” he said.

From Slate ● Sep. 22, 2026

“Claim they eat livestock. Kill pets, wild game. Not a whit of truth to it. I seen ’em eat dilly bugs and the like.

From "Willodeen" by Katherine Applegate

Now it has become a museum called Trent Park House of Secrets, which highlights the role of the team of German speakers, most of them Jewish refugees, who transcribed titbits from the prisoners' bugged conversations.

From Barron's ● Aug. 5, 2026

The couple kept close tabs on their permit applications and bugged Los Angeles County when they felt things weren’t moving fast enough.

From The Wall Street Journal ● Jun. 20, 2026

He inserted himself into the talks, arranging meetings in a bugged office building that allowed federal agents to record every word.

From Los Angeles Times ● Sep. 27, 2025

He dated actress Amber Heard, giving her Teslas as gifts, but she later worried they were bugged, because she said he was "controlling."

From Salon ● Mar. 12, 2025

Kadiatu cried as she gazed about the room, eyes bugged out with panic.

From "Taking Flight: From War Orphan to Star Ballerina" by Michaela DePrince

“Everybody’s been bugging me. They’re saying, ‘Would you do me a favor?

From The Wall Street Journal ● Sep. 16, 2026

Nature-loving travelers from around the globe are bugging out over the fireflies, descending en masse on isolated stretches of the U.S.

From The Wall Street Journal ● Jun. 3, 2026

“What is bugging me is I think our voter rolls may be more accurate than this database,” Phillips said.

From Salon ● Feb. 27, 2026

She insisted she was not in the least bit techy and was able to build her company after a lot of sleepless nights, research and "bugging people" who know about tech.

From BBC ● Dec. 14, 2025

Except that she’s trying to send a message about needing space from him, and he isn’t hearing it, and now it’s bugging her.

From "A Heart in a Body in the World" by Deb Caletti

Related Words

• breakdown
• defect
• error
• failure
• flaw
• problem
• trouble