immaturely

/ˌɪməˈtʃʊrli/
adverb
  1. In a way that shows a lack of emotional or mental development; childishly.
    • He immaturely refused to speak to anyone after losing the game.
    • She immaturely giggled during the serious presentation.
    • Instead of discussing the problem, they immaturely blamed each other.
Antonyms