infantile

/ˈɪnfənˌtaɪl/
adjective
  1. Relating to or typical of a very young child or baby.
    • The museum has a section on infantile development and early learning.
    • The pediatrician specializes in infantile diseases.
    • Her infantile laughter filled the room with joy.
  2. Childish, immature, or silly in a way that is not appropriate for an adult.
    • His infantile behavior during the meeting embarrassed everyone.
    • She found his constant whining to be utterly infantile.
    • Stop making those infantile jokes; we need to focus on the problem.
Antonyms