DictionaryAI

unable

un-AY-buhl/ʌnˈeɪbl̩/

3 meanings of unable

Practice

  1. 1
    adjective
    Lacking the ability, power, or opportunity to do something.

    He felt unable to express how grateful he really was.

    Many residents were unable to leave the flooded town in time.

    UsageUsually unable to + verb: unable to sleep. Incapable takes of + -ing instead: incapable of lying.

    Similarpowerless, incapable, helpless

    Oppositeable, capable

Less common meanings

  1. 2
    interjection
    Used, especially in radio communication, to indicate that a requested action cannot be carried out.
  2. 3
    verbnonstandard
    To deprive a person or thing of the ability to act or function; to disable.

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Origin

From Middle English unable (also spelled unabel, unhable, unhabil), formed from un- plus able.

Checked 6 Nov 2026 · 1 fact

  • The adjective descends from Middle English unable, also spelled unabel, unhable and unhabil, and consists of un- plus able. en.wiktionary.org