What is Another word that has the same root as unreasonable?

The root of "unreasonable" is "reason". Here are some words with the same root:

* Reason (noun): the power of the mind to think, understand, and form judgments.

* Reasonable (adjective): based on or using reason.

* Reasoning (noun): the process of thinking about something in a logical way.

* Reasonably (adverb): in a reasonable way.

* Disreason (noun): lack of reason; illogical thought.

* Reasonless (adjective): without reason; irrational.

These words all relate to the idea of logic, thought, and judgment.