Wiktionary
a. (context of thought etc. English) below or not fully rational; almost logical or reasonable.
Usage examples of "subrational".
Technical College employed Scholar of Subrational Mathematics Aelliana Caylon with pride, so the director often said.
Learned Scholar of Subrational Mathematics Aelliana Caylon, lately resolved to flee her homeworld for the comforts of a Terran settlement, spoke not one word of Standard Terran, nor any of the numerous Terran dialects.
How unfortunate, that you were not able to give Honored Scholar of Subrational Mathematics Aelliana Caylon her full bow, upon introduction.
It is better for observing their variations, from the scientific point of view, and it is safer for us if they remain disunited, for being rational they might develop a science, and being subrational it might be dangerous for us and for themselves if they did so.
Even the subrational himself sensed trouble on the right-hand side of the page somewhere in all that big type.