Skip to Content


Pronunciation: i-rash'un-al

Definition: Not rational; unreasonable (contrary to reason) or unreasoning (not exercising reason).

[L. irrationalis, without reason]

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.