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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

On Saturday the FDA said lettuce from a batch that Taylor Farms hadn’t recalled tested positive for the bug, suggesting the problems were broader.

From The Wall Street Journal ● Jul. 22, 2026

“It lasts much longer than a stomach bug where you’re sick for a day and you bounce back.”

From The Wall Street Journal ● Jul. 17, 2026

If you’re unlucky enough to have gotten the bug yourself, pretty bad!

From Slate ● Jul. 17, 2026

The lawsuit claims that Liu did not return an Apple-issued work laptop and exploited a “rare, previously unknown” bug to access Apple’s shared network folders while employed at OpenAI.

From MarketWatch ● Jul. 10, 2026

“Yep. The little guy seemed kind of lonely in the kennel, so I made a sling for him out of one of my old T-shirts last night. See? Snug as a bug in a rug.”

From "A Boy Called Bat" by Elana K. Arnold

Bug hotels designed to look like local landmarks have appeared near a Leeds train station.

From BBC ● Apr. 23, 2026

Around 2:30 a.m., two counselors from Bug House, the cabin nearest the river, ran to the office to tell Edward and Dick that water was leaking in.

From The Wall Street Journal ● Apr. 18, 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

“Remember, Ally Bug, I love you. There isn’t anything in the world I love more than you, your brother, and your mom.”

From "Fish in a Tree" by Lynda Mullaly Hunt

"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 BBC ● Jul. 15, 2026

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

Frustrated bettors have complained about bugs that prevent them from withdrawing funds.

From The Wall Street Journal ● Jul. 12, 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

“The children are not feeling well,” she said, trying not to look, for the thought of bugs in the flour threatened to put her off her own breakfast.

From "The Interrupted Tale" by Maryrose Wood

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

But increasingly, I find myself getting bugged by a lot of things, no matter how trivial they are in the grand scheme.

From Los Angeles Times ● Jul. 1, 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 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

If it was up to me, we woulda bugged out right away like the rest of the Kings, but Jennica's too good for that.

From "How It Went Down" by Kekla Magoon

Detectives turned to a daring undercover operation - bugging Michael Stewart's home and car, placing listening devices on his brother's car, and sending two covert officers into Michael's life.

From BBC ● Jul. 10, 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

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

From BBC ● May 7, 2026

I’m like, “I have a headphone in my ear and I’m really busy working. You’re kind of bugging me right now.”

From Los Angeles Times ● Mar. 24, 2026

“There’s just one thing that keeps bugging me,” I say.

From "Red Flags and Butterflies" by Sheryl Azzam

Related Words

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