irrationalism
noun
ir·ra·tio·nal·ism i-ˈra-sh(ə-)nə-ˌli-zəm 
1
: a system emphasizing intuition, instinct, feeling, or faith rather than reason or holding that the universe is governed by irrational forces
2
: the quality or state of being irrational
irrationalist
i-ˈra-sh(ə-)nə-list
noun or adjective irrationalistic
i-ˌra-sh(ə-)nə-ˈli-stik
adjective 
Example Sentences
Recent Examples on the Web Hitchens would have seen opposition to the coronavirus vaccine as another manifestation of destructive irrationalism. 
Matthew Continetti, National Review, 26 Dec. 2021 This exercise forces you to succumb to the irrationalism of your silly heart. Mayukh Sen, Bon Appetit, 6 June 2018 My gut reaction is that these student mobbists manage to combine snowflake fragility and lynch mob irrationalism into one perfectly poisonous cocktail. Jay Willis, GQ, 9 Mar. 2018
Matthew Continetti, National Review, 26 Dec. 2021 This exercise forces you to succumb to the irrationalism of your silly heart. Mayukh Sen, Bon Appetit, 6 June 2018 My gut reaction is that these student mobbists manage to combine snowflake fragility and lynch mob irrationalism into one perfectly poisonous cocktail. Jay Willis, GQ, 9 Mar. 2018 Word History
First Known Use
1811, in the meaning defined at sense 1