# Meaning of *irrational* in English:

## irrational^{}

See synonyms for irrationalTranslate irrational into Spanish

### adjective

1Not logical or reasonable.

*‘irrational feelings of hostility’**‘Power sets the guidelines by which we measure what is reasonable and what is irrational.’**‘The more irrational and illogical someone becomes, the more logical and incisive I become.’**‘By absurd, I do not mean silly, but absurd as is in the illogical or irrational.’**‘Chris smiled, sure that Seth's fears were completely irrational.’**‘Home values have soared to high levels in many countries as irrational exuberance grips the markets.’**‘I am sort of notorious for my utterly irrational fears.’**‘Crowds and mobs are not completely irrational, but they have their own logic.’**‘But Delta's seemingly irrational behavior has a very logical explanation.’**‘Solutions that would seem logical to us would seem totally irrational to them.’**‘He had a very short fuse and he could be totally irrational at times.’**‘If it hadn't seemed so irrational, she would have begged him not to go.’**‘She had never known for her daughter to be so irrational, so crazy.’**‘Their hostility towards each other, however, was tangible and frequently led to quite irrational behaviour.’**‘Australians aren't at all used to visceral and irrational hatred directed at them.’**‘Without that insight, a supplier can encounter fewer surprises by evaluating even seemingly irrational scenarios.’**‘I believe that the seemingly irrational logic of the national can still promote everyday alliances and popular mobilizations.’**‘Identify and uproot irrational beliefs that lead you to place unrealistic demands on yourself.’**‘The author of the piece argues that our attitude towards it is mostly irrational prejudice.’**‘Booze and cocaine corroded his sanity and left him with a legacy of irrational behaviour.’**‘I have an irrational dislike of cell phones.’*

View synonyms**unreasonable**, illogical, groundless, baseless, unfounded, unjustifiable, unsound- 1.1Not endowed with the power of reason.
*‘Whenever you encounter a system that seems so irrational, you should ponder what's going on beneath the surface.’**‘Man is an irrational being, morals are irrational, and have no metaphysical foundation which make them "real" or worth paying any attention to.’*

2Mathematics

(of a number, quantity, or expression) not expressible as a ratio of two integers, and having an infinite and non-recurring expansion when expressed as a decimal. Examples of irrational numbers are the number π and the square root of 2.*‘What about a seed angle derived from the golden ratio, an irrational number?’**‘The square root of 2 is an irrational number because it can't be written as a ratio of two integers.’**‘How can mathematical concepts like points, infinitesimally small quantities, or irrational numbers be anything but products of our minds?’**‘He considered computation with irrational numbers and polynomials to be part of algebra.’**‘A transcendental number is an irrational number that is not a root of any polynomial equation with integer coefficients.’*

### noun

MathematicsAn irrational number or quantity; a surd.

*‘Eudoxus's definition of equal ratios corresponds exactly to the modern theory of irrationals.’**‘Whether such quirks in the irregularity of irrationals have any implications for number theory remains an open question for mathematicians.’**‘His commentary to Euclid is of interest because of its discussion of unordered irrationals.’**‘If we chop off an infinite cfe after a finite number of steps then we will create a rational approximation to the original irrational.’**‘Any finite segment can be continued to produce a rational and any finite segment can be continued to produce an irrational.’*

**Origin**

Late Middle English from Latin irrationalis, from in- ‘not’ + rationalis (see rational).

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