irrational

2 ENTRIES FOUND:

1ir·ra·tio·nal

adjective \i-ˈra-sh(ə-)nəl, ˌi(r)-\

: 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>
ir·ra·tio·nal·i·ty \-ˌra-shə-ˈna-lə-tē\ noun
ir·ra·tio·nal·ly \-ˈra-sh(ə-)nə-lē\ adverb

Examples of IRRATIONAL

  1. He became irrational as the fever got worse.
  2. She had an irrational fear of cats.

Origin of IRRATIONAL

Middle English, from Latin irrationalis, from in- + rationalis rational
First Known Use: 14th century

2irrational

noun

Definition of IRRATIONAL

1
:  an irrational being

First Known Use of IRRATIONAL

1646

Rhymes with IRRATIONAL

ir·ra·tio·nal

adjective \(ˈ)ir-ˈ(r)ash-nəl, -ən-əl\   (Medical Dictionary)

Medical Definition of IRRATIONAL

: not rational: as a : 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>
ir·ra·tio·nal·i·ty \(ˌ)ir-ˌ(r)ash-ə-ˈnal-ət-ē\ noun, plural ir·ra·tio·nal·i·ties
ir·ra·tio·nal·ly \(ˈ)ir-ˈ(r)ash-nə-lē, -ən-əl-ē\ adverb

Browse

Next Word in the Dictionary: irrationalism
Previous Word in the Dictionary: irrationable
All Words Near: irrational

Seen & Heard

What made you want to look up irrational? Please tell us where you read or heard it (including the quote, if possible).

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More