Definition of childishness in English:

childishness

noun

  • See childish

    • ‘Little did she know that Alex loved her childishness and jovialness.’
    • ‘That may sound simple to the point of childishness.’
    • ‘I think that childishness and honesty is what the play is all about.’
    • ‘Her ignorance and her childishness were incredible.’
    • ‘Apart from the childishness of this, I can see what their issue is.’

Pronunciation

childishness

/ˈtʃʌɪldɪʃnəs/