WordGarden.ioirrational
B2Pronunciation
UK
- /ɪrˈæʃənəl/
US
- /ˌɪˈræʃənəl/
Meanings
Adjective
not based on reason or clear thinking
describing a number that cannot be expressed as a ratio of integers
Beyond the definition
Sometimes people act in ways that do not make sense. This word describes behavior, thoughts, or feelings that are not guided by clear reason. Often, strong emotion takes over. A fear of spiders can be common, but an irrational fear might mean panicking at the sight of a tiny spider across the room, even when you know it cannot hurt you.
It can describe people, beliefs, or actions. For example, if someone makes a big life decision based only on a "lucky feeling" and ignores the real facts, that choice would be irrational. The idea behind the word is simple: reason gives you solid ground, and this word suggests that solid ground is missing.
The word "irrational" describes something that isn't based on reason or logic. It suggests a departure from clear thinking and sound judgment, often driven by intense emotions, impulses, or unfounded beliefs. For example, "His irrational anger led him to say things he later regretted" indicates that his temper overwhelmed his ability to think clearly.
Irrationality can manifest in many ways. An irrational fear, such as a phobia, is an extreme and disproportionate reaction to something that poses little actual danger. Similarly, an irrational decision might be one made without considering the consequences or one based on faulty, biased information.
In the world of mathematics, "irrational numbers" are those that cannot be expressed as a simple fraction, or a ratio of two integers. Examples include pi (π) and the square root of 2. These numbers have infinite, non-repeating decimal expansions. In this mathematical sense, the word points to something that cannot be written as a ratio.
In everyday language, however, we primarily use "irrational" to describe human behavior or stubborn beliefs. It implies a lack of sound reasoning, regardless of whether numbers are involved. Someone who stubbornly clings to a theory despite overwhelming evidence to the contrary is acting irrationally. Whether you are discussing fears, decisions, or mathematics, calling something "irrational" highlights the gap between objective logic and subjective impulse.
Examples
- 1
Fear
After the accident, she had an irrational fear of driving at night.
- 2
Practical decision
It would be irrational to quit your job before you have another way to pay rent.
- 3
Emotions
He knew his anger was irrational, but he still felt embarrassed and defensive.
- 4
Personal reaction
Her reaction seemed irrational to everyone else, but it made sense to her at the time.
More examplesFewer examples
- 5
Travel delay
Try not to be irrational about the delay; the train company cannot control the weather.
- 6
Mathematics
In math class, we learned that pi is an irrational number.
See also
Similar
Shades of meaning
Contrast
Used with (collocations)
- irrational fear
- irrational behavior
- irrational decision
Word family
Explore
- cognitive bias
- reasoning
Forms and spellings
1 form open this card.
Main spelling
- irrationaladjectivenoun