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1

irrational

play
adjective ir·ra·tio·nal \i-ˈra-sh(ə-)nəl, ˌi(r)-\

Simple Definition of irrational

  • : not thinking clearly : not able to use reason or good judgment

  • : not based on reason, good judgment, or clear thinking

Source: Merriam-Webster's Learner's Dictionary

Full Definition of irrational

  1. :  not rational: as a (1) :  not endowed with reason or understanding (2) :  lacking usual or normal mental clarity or coherence b :  not governed by or according to reason <irrational fears> c Greek & Latin prosody (1) of a syllable :  having a quantity other than that required by the meter (2) of a foot :  containing such a syllable d (1) :  being an irrational number <an irrational root of an equation> (2) :  having a numerical value that is an irrational number <a length that is irrational>

irrationality

play \-ˌra-shə-ˈna-lə-tē\ noun

irrationally

play \-ˈra-sh(ə-)nə-lē\ adverb

Examples of irrational in a sentence

  1. He became irrational as the fever got worse.

  2. She had an irrational fear of cats.



Origin and Etymology of irrational

Middle English, from Latin irrationalis, from in- + rationalis rational


First Known Use: 14th century


2

irrational

noun ir·ra·tio·nal

Definition of irrational

  1. 1 :  an irrational being

  2. 2 :  irrational number



1646

First Known Use of irrational

1646


IRRATIONAL Defined for Kids

irrational

play
adjective ir·ra·tio·nal \i-ˈra-shə-nəl\

Definition of irrational for Students

  1. 1 :  not able to reason <The fever made him irrational.>

  2. 2 :  not based on reason <irrational fears>

irrationally

adverb



Medical Dictionary

irrational

play
adjective ir·ra·tio·nal \(ˈ)ir-ˈ(r)ash-nəl, -ən-əl\

Medical Definition of irrational

  1. :  not rational: asa:  lacking usual or normal mental clarity or coherence <was irrational for several days after the accident>b:  not governed by or according to reason <irrational fears>

irrationality

\(ˌ)ir-ˌ(r)ash-ə-ˈnal-ət-ē\play noun plural

irrationalities

irrationally

\(ˈ)ir-ˈ(r)ash-nə-lē, -ən-əl-ē\play adverb



Law Dictionary

irrational

play
adjective ir·ra·tio·nal \ir-ˈra-shə-nəl\

Legal Definition of irrational

  1. :  not rational: as a :  not governed by reason, mental clarity, or understanding b :  not governed by a fair consideration of facts or evidence; broadly :  arbitrary <an irrational decision to deny the permit>

irrationality

\ir-ˌra-shə-ˈna-lə-tē\ play noun

irrationally

adverb




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