1. lacking in reason: contrary to or lacking in reason or logic
2. lacking logical thought: unable to think logically
3. unable to think clearly: lacking the normal ability to think clearly, especially because of shock or injury to the brain
4. mathematics containing irrational number: describes a mathematical expression that contains an irrational number
5. poetry containing metric irregularity: describes an irregularity in the meter of a classical poem, usually where there is a long foot instead of a short one
noun (pluralir·ra·tion·als)
Definition:
1. irrational person: an unclear or illogical thinker