puerile
Meaning: juvenile, immature
Usage: The judge demanded order after the lawyer’s puerile attempt to object by stomping his feet on the courtroom floor.
sophomoric
Meaning: immature, uninformed
Usage: The mature senior rolled her eyes at the sophomoric gross-out humor of the underclassman.
juvenile
Meaning: childish or immature
Usage: The teacher ignored the juvenile joke and continued the lesson.
callow
Meaning: immature and inexperienced
Usage: The callow intern gradually learned how to handle difficult questions.
childish
Meaning: immature or typical of a child
Usage: The argument ended when both students realized their behavior was childish.