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dunno

v. · n.
US //dəˈnoʊ// UK //dˈʌnəʊ// dun·no
  1. 1 do not know (v.)
    A2 Elementary Informal Slang

    a short, informal way to say you do not know something.

    a contraction of 'do not know' or 'does not know', typically used in informal writing to mimic casual speech patterns.

    Example

    I dunno where I left my keys, but they aren't on the table.

    Example

    When asked about the missing files, he just shrugged and said 'I dunno' before walking away.

    Usage

    Primarily used in the first person ('I dunno') but occasionally used for third person ('he dunno').

    Teacher's tip

    Learners should be warned that while common in speech, 'dunno' can appear lazy or rude in formal contexts.
    Pitfall
    I dunno if I can come to the meeting.
    I don't know if I can come to the meeting.

    Avoid using 'dunno' in professional emails or formal essays; it is strictly for casual conversation or texting.

  2. 2 the utterance itself (n.)
    C1 Advanced Informal

    the act of saying the word 'dunno'.

    the verbalisation of the contraction 'dunno', often used to describe a vague or unhelpful response.

    Example

    All I got from him was a quick 'dunno' and a shrug.

    Example

    The witness offered nothing but a series of 'dunnos' during the cross-examination, frustrating the legal team.

    Usage

    Usually functions as a countable noun referring to the specific instance of the word being spoken.
Origin

Written form of an informal pronunciation of don't know that is a reduction of do not know or does not know.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Last updated June 20, 2026