behavior

American  

[bih-heyv-yer] / bɪˈheɪv yər /

especially British, behaviour

noun

1. manner of behaving or acting.

   Synonyms:

   carriage, bearing, demeanor

2. Psychology, Animal Behavior.

   1. observable activity in a human or animal.

   2. the aggregate of responses to internal and external stimuli.

   3. a stereotyped, species-specific activity, as a courtship dance or startle reflex.

3. Often behaviors. a behavior pattern.

4. the action or reaction of any material under given circumstances.

   the behavior of tin under heat.

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behavior Scientific  

/ bĭ-hāv′yər /

1. The actions displayed by an organism in response to its environment.

2. One of these actions. Certain animal behaviors (such as nest building) result from instinct, while others (such as hunting) must be learned.

3. The manner in which a physical system, such as a gas, subatomic particle, or ecosystem, acts or functions, especially under specified conditions.

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behavior Idioms  

1. see on one's best behavior.

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Synonym Usage

Behavior, conduct, deportment, comportment refer to one's actions before or toward others, especially on a particular occasion. Behavior refers to actions usually measured by commonly accepted standards: His behavior at the party was childish. Conduct refers to actions viewed collectively, especially as measured by an ideal standard: Conduct is judged according to principles of ethics. Deportment is behavior related to a code or to an arbitrary standard: Deportment is guided by rules of etiquette. The teacher gave Susan a mark of B in deportment. Comportment is behavior as viewed from the standpoint of one's management of one's own actions: His comportment was marked by a quiet assurance.

Other Word Forms

Derived Forms

• behavioral
  adjective
• interbehavior
  noun

Etymology

Origin of behavior

First recorded in 1375–1425; behave ( def. ) + -ior (on model of havior, variant of havor, from Middle French (h)avoir “a having,” ultimately from Latin habēre “to have”); replacing late Middle English behavoure, behaver; see -or ¹ ( def. )

Explanation

Behavior refers to how you conduct yourself. Generally, it’s wise to engage in good behavior, even if you're really bored. The noun behavior is a spin-off of the verb behave. Get rid of the be in behave and you're left with have, which makes sense: you could say that to behave is to "have" or "own" yourself — to control yourself. There's also a broader definition of behavior, which is basically anything any living thing does in any situation. Brushing your teeth? Behavior. Scratching your nose? Behavior. Eating a large antelope because you are a lion and you're hungry? Also behavior.

Example Sentences

“I feel terrible about what happened. I feel really bad about my actions and some of the terrible behavior I did,” he said.

From Los Angeles Times • Jun. 6, 2026

It was around that period that he dated Fifield, a Republican former campaign aide whose accusation was published by the New York Times in an article that included claims of bad behavior from other women.

From The Wall Street Journal • Jun. 6, 2026

Yet all of these arguments depend, in large part, on surface-level behavior.

From Science Daily • Jun. 5, 2026

After all that, it’s hard to believe he’s telling the truth when he denies alleged behavior that neatly tracks with the rest of the emerging picture of his character.

From Slate • Jun. 5, 2026

The first person inside AIG FP to awaken to the madness of his firm’s behavior, and sound an alarm, was not Tom Fewings, who quickly forgot his meeting with Lippmann, but Gene Park.

From "The Big Short" by Michael Lewis

Related Words

• act
• action
• attitude
• conduct
• demeanor
• management
• nature
• performance
• practice
• presence
• role
• style