DictionaryAI

behaviour

noun
UKbi-HAY-vyuh/bɪˈheɪ.vjə(ɹ)/bi-HAY-vyer/bɪˈheɪ.vjɚ/

Pluralbehaviours

US spellingbehavior

4 meanings of behaviour

Practice

  1. 1
    how someone actsnouncountable or uncountable
    The way a person or animal acts, or one particular thing they do, especially when it is watched or studied.

    Our dog's behaviour changed after the new baby came home.

    The farmer watches the behaviour of his cows when a storm is coming.

    UsageMost people say his behaviour; scientists also say behaviours for single actions.

    Similaractions, demeanour

  2. 2
    good or bad conductnoununcountable
    The way a person acts, judged by what people think is right or polite.

    The teacher said our behaviour in class was much better this week.

    Shouting at the waiter like that was really rude behaviour.

    UsageSay good behaviour or bad behaviour, usually without a.

    Similarconduct, manners

  3. 3
    non-living thingsnoununcountable
    The way a machine, system or material works or changes, especially in certain conditions.

    My phone's behaviour has been very strange since I dropped it.

    Engineers watched the behaviour of the bridge in strong winds.

    Similarperformance, operation, functioning

Less common meaning

  1. 4
    best mannersnoununcountable
    Acting as well and as politely as you can, usually because people are watching you.

    The boys were on their best behaviour when the head teacher walked in.

    I'll be on my best behaviour at the dinner, I promise.

    UsageSay on my best behaviour, on her best behaviour and so on.

Practice

Can you tell the meanings of behaviour apart? Answer 3 quick questions from this page, or write your own sentence and AI will check it.

Origin

It comes from the Middle English verb behaven, which became behave. Its ending seems to copy an old word, havour, meaning “a having”.

Checked 5 Nov 2026 · 4 facts