not competent; lacking qualification or ability; incapable: an incompetent candidate.
characterized by or showing incompetence: His incompetent acting ruined the play.
  1. being unable or legally unqualified to perform specified acts or to be held legally responsible for such acts.
  2. inadmissible, as evidence.


an incompetent person; a mentally deficient person.
Law. a person lacking power to act with legal effectiveness.

Origin of incompetent

1590–1600; < Late Latin incompetent- (stem of incompetēns) unsuitable. See in-3, competent
Related formsin·com·pe·tent·ly, adverb

Synonyms for incompetent

Antonyms for incompetent Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for incompetent

Contemporary Examples of incompetent

Historical Examples of incompetent

British Dictionary definitions for incompetent



not possessing the necessary ability, skill, etc to do or carry out a task; incapable
marked by lack of ability, skill, etc
law not legally qualifiedan incompetent witness
(of rock strata, folds, etc) yielding readily to pressure so as to undergo structural deformation


an incompetent person
Derived Formsincompetence or incompetency, nounincompetently, adverb
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 incompetent

1610s, "insufficient," from French incompétent, from Late Latin incompetentem (nominative incompetens) "insufficient," from in- "not" (see in- (1)) + Latin competentem (see competent). Sense of "lacking qualification or ability" first recorded 1630s. The noun meaning "incompetent person" is from 1866. Related: Incompetently.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for incompetent




Inadequate for or unsuited to a particular purpose or application.
Incapable of proper functioning.
Not qualified in legal terms.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.