Definition of "guilelessness"

They'd say he was operating behind a screen of guilelessness and was a superhypocrite.

1987, Saul Bellow, More Die of Heartbreak

You have to give director Colm McCarthy, a Scottish TV veteran making his feature film debut, and writer Mike Carey, adapting his own novel, credit for attempting the seemingly impossible task of doing something new with the zombie subgenre. And by blending it with the common YA trope of a young female protagonist who leads the world into a new revolutionary era, they almost get there—largely thanks to newcomer Nanua, who presents her character’s grappling with complex themes of identity and original sin with a childlike guilelessness.

2017 February 23, Katie Rife, “The Girl With All The Gifts tries to put a fresh spin on overripe zombie clichés”, in The Onion AV Club‎