unboyishly

Thereafter, in that little gallery of mental portraits carried by each of us in his intimate heart, the beloved form of his dead mother was given a companion picture: that of a girl's face, warm and living, upon which he often gazed with an ardor, a devotion, a longing, rather unboyishly sincere.

The Genius Margaret Horton Potter

It was the uselessness of Big Jim's death that made the boy unboyishly bitter.

Still Jim Honor�� Morrow 1910

Josh was a brave boy and growing strong, but unboyishly grave with the weight of care.

Children's Literature A Textbook of Sources for Teachers and Teacher-Training Classes Charles Madison Curry 1906

Josh was a brave boy and growing strong, but unboyishly grave with the weight of care.

Wild Animals at Home Ernest Thompson Seton 1903