Resembling or evocative of a children's adventure story; characterized by daring and heroism; exciting.
Sometimes also with the implication of implausibility or simplistic naivety..
Origin
1960s; earliest use found in David Pinner (b. 1940). From the genitive of boy + own, after the name of The Boy's Own Paper, a weekly publication aimed at young and teenage boys which frequently featured stories of adventure and daring, published from 1879 to 1967.