irrational

Meanings

1. 1
   adj

   Not based on clear thinking or good reasons

   He has an irrational fear of spiders.

2. 2
   adj

   In maths, describing a number that cannot be written as a simple fraction

   The number pi is irrational.

3. 3
   noun

   In maths, a number that cannot be written as a fraction of two whole numbers

   The square root of two was the first irrational the Greeks discovered.

From Latin irratiōnālis, from ir- + ratiōnālis.

Topics