not logical; contrary to or disregardful of the rules of logic; unreasoning: an illogical reply.

Origin of illogical

First recorded in 1580–90; il-2 + logical
Related formsil·log·i·cal·ly, adverbil·log·i·cal·ness, noun

Synonyms for illogical Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for illogical

Contemporary Examples of illogical

Historical Examples of illogical

  • From it, a thousand wild, illogical, and fantastic conclusions are drawn.

  • This is possible, it is not illogical, and Berkeley believes it.

  • He was only misled by his love of antithesis into a hasty and illogical remark.

    Wilfrid Cumbermede

    George MacDonald

  • Plato saw the necessity of combating the illogical logic of the Megarians and Eristics.

  • That, of course, was illogical; but you can hardly expect logic from a man in his position.

    Captain Blood

    Rafael Sabatini

British Dictionary definitions for illogical



characterized by lack of logic; senseless or unreasonable
disregarding logical principles
Derived Formsillogicality (ɪˌlɒdʒɪˈkælɪtɪ) or illogicalness, nounillogically, 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 illogical

1580s, from assimilated form of in- (1) "not, opposite of" + logical. Related: Illogically.

Online Etymology Dictionary, © 2010 Douglas Harper