Definitions:

1. A mark or point against someone, typically used in the context of evaluating behavior, performance, or conduct, especially in educational or disciplinary settings. NOUN
   • The demerit system implemented by the school aims to encourage students to maintain discipline and academic integrity.
2. Something that deserves blame or lacks merit. NOUN
   • One demerit of living in a bustling city is the constant noise pollution.
3. The quality of being inadequate or falling short of perfection. NOUN
   • They often discussed the merits and demerits of classic novels.

Synonyms:

• bad mark
• deficiency
• degrade
• demote
• downgrade
• fault
• loss of credit
• punishment
• shortcoming