Source : Webster's Revised Unabridged Dictionary (1913)

Puerile \Pu"er*ile\, a. [L. puerilis, fr. puer a child, a boy:
   cf. F. pu['e]ril.]
   Boyish; childish; trifling; silly.

         The French have been notorious through generations for
         their puerile affectation of Roman forms, models, and
         historic precedents.                     --De Quincey.

   Syn: Youthful; boyish; juvenile; childish; trifling; weak.
        See {Youthful}.

Source : WordNet®

puerile
     adj 1: of or characteristic of a child; "puerile breathing"
     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}]