Puerile – Immature; behaving in a silly and childish way

To remember the definition of the word puerile, use the following mnemonic:

She did this purely to rile (puerile) me up, she's so childish.

Examples of puerile in a sentence

My daughter is 32 years of age, I do not find her puerile behaviour amusing.

Kayley got drunk and she showed everyone how puerile she really was.

Your jokes are puerile and not appropriate for a man of your stature.