邻家女流氓
[lín jiā nǚ liú máng]
A playful oxymoron combining two different ideas: neighbor's girl, giving an innocent image of an everyday person one would encounter near home (a next-door neighbor); versus hooligan or ruffian which indicates naughtiness, mischief, or breaking norms. Overall it suggests someone who has the appearance of sweetness but behaves naughtily and humorously in a harmless way.