Puerilely is an uncommon adverb which means to behave childishly or in a silly or immature way. There are several synonyms that can be used to express this behavior, such as childishly, immaturely, stupidly, foolishly, naively, or in a puerile way. Childishly can be used to describe behavior that is characteristic of a child, while immaturely describes behavior that is not fully developed or mature. Stupidly is used to describe behavior that lacks intelligence or common sense, while foolishly describes behavior that is lacking in judgment or wisdom. Naively suggests that a person is inexperienced or unworldly, while puerilely pertains to behavior that is silly or trivial.