behavior

noun

be·​hav·​ior bi-ˈhā-vyər 

bē-

1

: the way in which someone conducts oneself or behaves (see behave sense 1)

We were grateful for the gracious behavior of our hostess.

The children were rewarded for good behavior.

Be on your best behavior.

also : an instance of such behavior

unacceptable social behaviors

2

a

: the manner of conducting (see conduct entry 1 sense 2) oneself

criminal behavior

normal adolescent behavior

b

: anything that an organism does involving action and response to stimulation

c

: the response of an individual, group, or species to its environment

They are studying the behavior of elephants in the wild.

3

: the way in which something functions or operates

They tested the behavior of various metals under heat and pressure.

Synonyms

• actions
• demeanor
• attitude

Examples of behavior in a Sentence

I'm surprised by her bad behavior toward her friends.

Students will be rewarded for good behavior.

scientists studying the behavior of elephants

An acceptable social behavior in one country may be unacceptable in another country.

Doctors are trying to educate people about behaviors that can put them at increased risk for skin cancer.

The experiment tested the behavior of various metals under heat and pressure.

Recent Examples on the Web

At Bock Realty Group, trust is built in the small, consistent behaviors that often go unnoticed: celebrating wins, checking in without being asked, and showing up with steady care. —Alain Hunkins, Forbes.com, 1 July 2025

The intense exchange between Kemp, 48, and Rock, 25, took place early Tuesday (July 1) morning, with Rock allegedly calling the social media personality to seemingly address Kemp’s remarks regarding her behavior and parenting of her son with rapper Blueface, who is currently incarcerated. —Jessica Bennett, VIBE.com, 1 July 2025

The post has prompted more than 1,700 comments, many expressing admiration for the male cat's attentive behavior and the emotional bond on display. —Melissa Fleur Afshar, MSNBC Newsweek, 30 June 2025

Kling said she’s seen an increase in some negative behaviors, such as people running more red lights, that need to be addressed. —Nick Rosenberger, Idaho Statesman, 30 June 2025

Word History

Etymology

alteration of Middle English behavour, from behaven "to behave" + -our -or entry 2

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing behavior

• behavior modification
• behavior therapy
• cognitive behavior therapy
• for good behavior
• on one's best behavior
• on their best behavior

Rhymes for behavior

• behaviour
• havior
• savior
• saviour
• misbehavior
• misbehaviour

Kids Definition

behavior

noun

be·​hav·​ior bi-ˈhā-vyər 

1

: the way in which one conducts oneself

2

: the way in which something (as a machine) behaves

3

: anything that a living being does that involves action and response to stimulation

behavioral

-vyə-rəl 

adjective

Medical Definition

behavior

noun

be·​hav·​ior

variants or chiefly British behaviour

bi-ˈhā-vyər 

1

: the manner of conducting oneself

2

a

: anything that an organism does involving action and response to stimulation

b

: the response of an individual, group, or species to its environment

behavioral adjective

or chiefly British behavioural

-vyə-rəl 

behaviorally adverb

or chiefly British behaviourally

-rə-lē