Luciana fled mirthfully along the sidewalk in her high white wedgies, pulling Yossarian along in tow with the same lusty and ingenuous zeal she had displayed in the dance hall the night before and at every moment since.
There are no more uses of "ingenuous" in the book.
Show samples from other sources
She plays a wide-eyed, ingenuous schoolgirl forced to grow up too quickly.
The face of the old man was stern, hard-featured, and forbidding; that of the young one, open, handsome, and ingenuous.
Dickens, Charles -- The Life and Adventures of Nicholas Nickleby