1. the quality or state of being harmful, destructive, or having a gradual but severe negative effect

Examples

• The perniciousness of misinformation spreads slowly but causes lasting damage to public trust.
• Doctors warned about the perniciousness of untreated diabetes, which silently damages organs over time.
• The perniciousness of corruption in government undermines democratic institutions.
• Scientists study the perniciousness of certain pollutants that accumulate in the body.
• The perniciousness of social media addiction affects mental health in subtle but significant ways.
• He argued that the perniciousness of prejudice lies in its ability to persist across generations.