puerilism

/ˈpjuːərɪlɪzəm/
noun
  1. Behavior or attitudes that are childish or immature, especially in an adult.
    • She outgrew her puerilism and became a responsible team leader.
    • The politician's puerilism during the debate embarrassed his supporters.
    • His constant puerilism at work made his colleagues take him less seriously.
Antonyms
What does "puerilism" mean? | whatsthatwordmean | whatsthatwordmean