Select the most appropriate one-word substitution for the given group of words. 

An act of  failure to do one's job or duty.

Dereliction

The most appropriate one-word substitution for an act of failure to do one's job or duty is dereliction.

• Addiction is a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences.
• Dedication is the act of giving oneself completely to a task or purpose.
• Entomology is the scientific study of insects.

The word dereliction is derived from the Latin word delinquere, meaning "to neglect". It is the failure to do something that one is required or expected to do, especially a duty or responsibility. Dereliction can be intentional or unintentional, and it can have serious consequences.