1. not having the qualities typically associated with children; lacking childish innocence, simplicity, or naturalness

Examples

• Her unchildlike wisdom surprised the adults at the dinner table.
• The boy’s unchildlike behavior made him seem older than his years.
• There was something unchildlike about the way she analyzed the situation.
• His unchildlike cynicism was troubling for someone so young.
• The painting had an unchildlike complexity that impressed the critics.
• She spoke with an unchildlike seriousness about the family’s problems.