unreason

Short definition from Wiktionary

Noun

1. 1
   Lack of reason or rationality; unreasonableness; irrationality.
2. 2
   Nonsense; folly; absurdity.

Verb

1. 1
   To prove to be unreasonable; disprove by argument.
2. 2
   To apply false logic or think without logic.
3. 3
   To make unreasonable; to deprive of reason.