Irrationality (noun)

The quality or state of being illogical, unreasonable, or lacking sound judgment.

Origin:

The word 'irrationality' comes from the latin word 'irrationalitas' and was first used in english in the 16th century.

Examples:

1. The decision was plagued by irrationality and seemed to make no sense.
2. Her irrationality was causing problems in their relationship.
3. His irrationality was causing him to make poor business decisions.
4. The irrationality of the policy was causing widespread confusion.
5. The irrationality of the argument made it difficult to have a productive conversation.