Dereliction is a word for neglecting responsibilities. Failing to care for your family or do your job are examples of dereliction.
If you are letting things go, you are engaged in dereliction. Not mowing your lawn is an example of dereliction; so is not feeding your children. Someone can be fired for dereliction of duty, meaning they have failed to do their job. Dereliction is the opposite of diligence, a quality of people who are hard-working. It might help you to remember this word if you know that homeless people are sometimes called derelicts, implying that they are not able to care for themselves.