Immature

• Puerile
• Mostly cold item on menu suitable for a youngster
• Almost cool meal suitable for infants
• Infantile learner withdrawn from cool course
• Briefly refrigerate babe? That's immature

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Childish \Child"ish\ (ch[imac]ld"[i^]sh), a. Of, pertaining to, befitting, or resembling, a child. ``Childish innocence.'' --Macaulay. Puerile; trifling; weak. Methinks that simplicity in her countenance is rather childish than innocent. --Addison. ...

Wiktionary Word definitions in Wiktionary
a. 1 Of or suitable for a child. 2 Behaving immaturely.

Wikipedia Word definitions in Wikipedia
Childish can refer to: Being like a child English writer and musician Billy Childish Rapper Childish Gambino Act of being petty