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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.  Also called 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

At the same time, we’ve been talking about how this is a bug that we don’t know much about, that didn’t use to show up on our shores.

From Slate ● Jul. 17, 2026

Meningitis infections can be spread through close contact - for example though kissing, sharing vapes and drinks or living in close quarters with a person with the bug.

From BBC ● Jul. 13, 2026

But some say traders who gravitate toward these products see big swings in the underlying stocks as a feature, not a bug.

From MarketWatch ● Jul. 9, 2026

Tyler officially caught the singing bug after placing second at the talent show hosted by a local rugby club.

From Los Angeles Times ● Jul. 9, 2026

“Pixies don’t bug you unless you’re near gold. They definitely don’t bite unless you have gold. Lots of it.”

From "Rump: The (Fairly) True Story of Rumpelstilskin" by Liesl Shurtliff

Bug hotels provide a safe habitat for insects and small creatures to shelter, hibernate and nest.

From BBC ● Apr. 23, 2026

Bug submissions are up 76% from last year and the average time to fix a bug has jumped from 160 days to 230 days during the same period, according to the company.

From The Wall Street Journal ● Apr. 14, 2026

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

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

“Beeg Bug take Boots ride!” she said, patting him more vigorously on the head.

From "Gregor the Overlander" by Suzanne Collins

The chasteness of Nolan’s version bugs me as it’s insulting he doesn’t trust audiences to grapple with this hero’s moral complexity — and I’m gut-sick that he’s probably right.

From Los Angeles Times ● Jul. 15, 2026

A battle between gold bugs and bullion bears appeared to be coalescing around the $4,000 an ounce mark on Tuesday, as the precious metal is on track to register its worst quarter in 13 years.

From MarketWatch ● Jun. 30, 2026

Another technical strategist thinks there could be more pain ahead for gold bugs as well.

From Barron's ● Jun. 24, 2026

As the walk ends, the group poses for a photo - holding a rainbow flag that reads "be queer, touch bugs" - and some participants exchange contact details.

From BBC ● Jun. 20, 2026

Seconds later, we were sitting in the yard watching the chickens peck for corn and bugs.

From "Root Magic" by Eden Royce

My department chairman intervened, and I avoided arrest—though a student later told me my apartment was likely bugged.

From The Wall Street Journal ● Jul. 7, 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

His agency-provided apartment comes bugged and his movements are tracked.

From Los Angeles Times ● Nov. 28, 2024

Vice Presidential nominee JD Vance told podcaster Joe Rogan on Thursday that he bugged out from a game of mini-golf after he heard of Donald Trump's assassination attempt.

From Salon ● Oct. 31, 2024

It always bugged him that she got the best room.

From "Small Steps" by Louis Sachar

An audio bugging device left by MI5 recorded the whole thing.

From BBC ● May 7, 2026

As though rich people don’t know how to activate the block feature on their phones, and as though bugging them is the way to get them to do what you want.

From The Wall Street Journal ● Apr. 29, 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

A spokesperson for ANL has previously said it had "denied under oath that its journalists had commissioned or obtained information derived from phone hacking, phone tapping, bugging, computer or email hacking or burglary to order".

From BBC ● Oct. 1, 2025

“But what does that mean? I am familiar with the concept of bugging out, but I do not think I have heard the word love before.”

From "A Rover's Story" by Jasmine Warga

Related Words

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