1. The head or skull.
Usage: British informal/slang; often used in a lighthearted or humorous way
2. Common sense or intelligence.
Usage: British informal; usually in the phrase 'use your bonce'

Examples

• He bumped his bonce on the low doorway.
• Use your bonce and think before you act.
• The footballer headed the ball with his bonce.
• She's got a good bonce on her shoulders.
• Mind your bonce—the ceiling is low here.