Wiktionary
antirational
a. Lacking or (qualifier: especially) opposed to reason and rational thought.
Usage examples of "antirational".
One only has to think of any antidemocratic, antirational or antihumane idea out of the Dark Ages,' Mama Sutra said, and one can immediately think of some popular religious columnist or some movie star who is blatantly expounding it and calling it "Americanism.