习气 refers to a negative habit or tendency that someone has developed over time, often through repeated behavior or exposure to a bad environment. It carries a stronger negative connotation than 习惯 (habit) and is typically used to criticize undesirable behaviors in a person or group, such as laziness, arrogance, or carelessness. You can use it in phrases like 官僚习气 (bureaucratic habits) or 坏习气 (bad habits).