All 6 Uses of

irrational
in
The Lords of Discipline

Almost all cadets, no matter how irreverently they referred to the war, were looking forward to leading troops into battle—it was the grand guignol of our generation, the testing ground of valor—and the collective eyes of the Corps were turned in an eagergaze toward Asia with all the blind irrational instincts of rutting boys, as new portraits began to arrive at the library each month, and as we began to recognize the faces in the portraits.†
Chpt 1.10

irrational = unreasonable

Since my father was a conservative of a particularly fevered strain, it was natural for me to study carefully every creed or doctrine to which he was irrationally and diametrically opposed.†
Chpt 1.11 *

irrationally = in a manner that is not reasonable

In the completeness of her loneliness, she was growing more petulant and irrational.†
Chpt 3.23

irrational = unreasonable

As I looked around the Hall, I felt irrationally close to my classmates who had come to the auditorium for the most meaningful ceremony of our careers as cadets at the Institute.†
Chpt 3.26

irrationally = in a manner that is not reasonable

She still wore her raincoat, out of habit, I suppose, or because it granted her some irrational protection against the movement of the universe that had enveloped her in its rhythm of change and time and inevitability.†
Chpt 4.31

irrational = unreasonable

It affects the way you view the world, and you worry irrationally about how you're going to pay your tuition or buy your uniforms or borrow enough money to pay for your ring.†
Chpt 4.41

irrationally = in a manner that is not reasonable

Definitions:

(1) (irrational)
not reasonable
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

More rarely, irrational numbers in mathematics are numbers that cannot be expressed as a fraction consisting of only an integer in the numerator and denominator. For example, pi is an irrational number while 1/3 is rational.