unreason vs irrationality

unreason and irrationality both are nouns.

Word	Noun	Adjective	Verb	Adverb
unreason	Yes	No	No	No
irrationality	Yes	No	No	No

As nouns, unreason and irrationality are synonyms defined as:

unreason and irrationality: the state of being irrational; lacking powers of understanding

unreason (noun)	irrationality (noun)
the state of being irrational; lacking powers of understanding	the state of being irrational; lacking powers of understanding