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The market's enthusiasm for high-tech stocks was irrational but understandable.
I knew I was being irrational, but when she was late I began to fear the worst.
This is the British English definition of irrational. View American English definition of irrational.
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View the pronunciation for irrational.
a small digital image … which is used in electronic communication to express emotion or other simple concepts
a complete failure
to have or do a lot of something; to focus on a particular thing
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Definition of irrational from the online English dictionary from Macmillan Publishers Limited.