1. childish behavior or thinking, especially when displayed by an adult
Usage: formal
2. a psychological condition characterized by regression to childlike behavior patterns
Usage: psychology; medical

Examples

• The politician’s puerilism was evident in his name-calling during the debate.
• Her constant giggling and silly jokes showed a disturbing puerilism for someone her age.
• The therapist diagnosed the patient with puerilism following the traumatic event.
• His puerilism made it difficult for colleagues to take him seriously in meetings.
• The novel explores themes of puerilism in modern society.
• Critics dismissed the artist’s work as mere puerilism disguised as avant-garde expression.