[uhn-ey-buh l]


lacking the necessary power, competence, etc., to accomplish some specified act: He was unable to swim.

Origin of unable

Middle English word dating back to 1350–1400; see origin at un-1, able

Synonyms for unable

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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Contemporary Examples of unable

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British Dictionary definitions for unable



(postpositive foll by to) lacking the necessary power, ability, or authority (to do something); not able
archaic incompetent
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for unable

late 14c., "lacking in ability, incapable," from un- (1) "not" + able. Modeled on Old French inhabile or Latin inhabilis.

Online Etymology Dictionary, © 2010 Douglas Harper