1. the quality or state of behaving like a brat; childish, spoiled, or ill-behaved conduct
Usage: informal; typically used to describe behavior considered immature or disrespectful

Examples

• The child's brattishness was on full display when she threw a tantrum over not getting the toy she wanted.
• His brattishness made him unpopular with his classmates.
• The teenager's brattishness improved once she started taking responsibility for her actions.
• We couldn't tolerate her brattishness any longer and set clear boundaries.
• His brattishness was evident in the way he complained about everything at dinner.
• The coach addressed the team's brattishness by requiring them to show respect and discipline.