Simple Definition of irrational
: not thinking clearly : not able to use reason or good judgment
: not based on reason, good judgment, or clear thinking
Full Definition of irrational
: 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>
Examples of irrational in a sentence
He became irrational as the fever got worse.
She had an irrational fear of cats.
Origin of irrational
Middle English, from Latin irrationalis, from in- + rationalis rational
First Known Use: 14th century
Definition of irrational
1 : an irrational being
IRRATIONAL Defined for Kids
Definition of irrational for Students
1 : not able to reason <The fever made him irrational.>
2 : not based on reason <irrational fears>
Medical Definition of irrational
: 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>
Legal Definition of irrational
: 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>
Seen and Heard
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