ir·ra·tio·nal /ir-'ra-shə-nəl/ adj: not rational: as
a: not governed by reason, mental clarity, or understanding
b: not governed by a fair consideration of facts or evidence; broadly: arbitrary
an irrational decision to deny the permit
ir·ra·tio·nal·i·ty /ir-ˌra-shə-'na-lə-tē/ n
ir·ra·tio·nal·ly adv
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.