'irrationalist' originates from the Latin word 'irrationalis,' where 'in-' meant 'not' and 'rationalis' meant 'reasonable or logical.'

'irrationalis' transformed into the French word 'irrationnel,' and eventually became the modern English word 'irrationalist' through Middle English.

Initially, it meant 'not reasonable or logical,' but over time it evolved into its current meaning of 'a person who prioritizes emotions or intuition over reason and logic.'