1. infected with pus; showing signs of decay or infection
2. growing worse; becoming increasingly problematic or resentful

1. to form or discharge pus; to become infected
2. to grow worse or more intense over time without being addressed

Examples

• The wound became festering after he failed to clean it properly.
• A festering sore on his foot made it painful to walk.
• The conflict has been festering for months without any attempt at resolution.
• If you don't address the problem now, it will keep festering and get worse.
• The festering resentment between the two neighbors finally erupted into an argument.
• The doctor drained the festering abscess to relieve the infection.
• Unresolved grievances tend to fester in relationships over time.