Wiktionary
n. The property of being level-headed.
Usage examples of "level-headedness".
She thought of her clerical father in his country parsonage, and of her mother’s death, and of her own determination to obtain education, and of her college life, which had merged, not so very long ago, in the wonderful maze of London, which still seemed to her, in spite of her constitutional level-headedness, like a vast electric light, casting radiance upon the myriads of men and women who crowded round it.
Mospheirans and atevi alike owed Stani Ramirez for his level-headedness against bad decisions in his own command structure—they owed him for his clear vision and his continual smoothing of the way ahead.
Then once again, she demonstrated her father's cool level-headedness under fire.
It is Mark's youngster level-headedness and humanity that throw into relief the adults’ absurdity and special cruelty.