irrational
irrational
Definition & meaning
Irrational means not based on reason or logic, or contrary to reasonable judgment. It can describe behavior, decisions, fears, or arguments that seem unreasonable.
In mathematics, an irrational number is a real number that cannot be expressed as a ratio of two integers. Its decimal expansion goes on indefinitely without repeating, as with √2 or π.
Grammar & Word origin
Irrational is an adjective. It can be inflected according to the noun it describes, for example irrationales Verhalten . It comes from Latin irrationalis: the prefix ir- expresses negation, and rational relates to reason or calculation.
Synonyms & antonyms
Synonyms:
- unvernünftig — unreasonable; often suggests poor judgment or a lack of practical sense.
- unlogisch — illogical; emphasizes a flaw in reasoning or consistency.
- vernunftwidrig — contrary to reason; a more formal synonym.
Antonyms:
- rational — based on reason, logic, or careful consideration.
- vernünftig — sensible or reasonable, often with a practical emphasis.
- logisch — logical or consistent in its reasoning.
Common phrases & collocations
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Examples
Sein Verhalten in der Situation war vollkommen irrational.adjective
His behavior in that situation was completely irrational.
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