1. That which is below standard or expectations as of ethics or decency
   "The badness of his behaviour shocked everyone";
   - bad
    
2. Used of the degree of something undesirable e.g. pain or weather
   "The badness of the storm caught everyone off guard";
   - severity, severeness [rare]
    
3. An attribute of mischievous children
   "The children's badness led to many broken windows";
   - naughtiness, mischievousness

Type of: disobedience, intensity, intensiveness, quality

Antonym: goodness