Spoiled, disobedient, or obnoxiously childish in behavior; acting like a brat.
From brat (a spoiled or naughty child) plus the adjective-forming suffix -y, which creates adjectives meaning 'having the quality of' or 'full of.' The word emerged in English around the 1800s.
Psychologists have noticed that 'bratty' is primarily used for children under 13—after that, we call the same behavior 'entitled' or 'selfish,' which shows language helps us excuse bad behavior in kids more than in teens or adults.
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