1. the deliberate failure to do what one should do, especially neglecting one’s duty or responsibility
2. the state of being abandoned and allowed to fall into disrepair

Examples

• The officer was court-martialed for dereliction of duty.
• His dereliction of parental responsibilities led to serious consequences.
• The building showed clear signs of dereliction after years of abandonment.
• The committee investigated the dereliction of safety protocols.
• Urban dereliction has become a major problem in the downtown area.
• She was fired for dereliction of her supervisory duties.
• The dereliction of the old factory made it a safety hazard.