1. of or characteristic of a child - puerile breathing • Pertains to noun: child • Derivationally related forms: puerility 2. displaying or suggesting a lack of maturity - adolescent insecurity - jejune responses to our problems - their behavior was juvenile - puerile jokes • Syn: adolescent, jejune, juvenile • Similar to: immature • Derivationally related forms: puerility, juvenility (for: juvenile), jejuneness (for: jejune), jejunity (for: jejune)