(Entry 1 of 2) : not rational: such as. a(1) : lacking usual or normal mental clarity or coherence. (2) : not endowed with reason or understanding. b : not governed by or according to reason irrational fears.

What does it mean when someone's being irrational?

Irrationality is cognition, thinking, talking, or acting without inclusion of rationality. ... The term is used, usually pejoratively, to describe thinking and actions that are, or appear to be, less useful, or more illogical than other more rational alternatives.

What is irrational example?

Irrational is defined as lacking reason or understanding. An example of irrational is a fear of a certain color. ... Designating a real number not expressible as an integer or as a quotient of two integers: √3 and pi are irrational numbers.