Euthanasia, also known as assisted suicide, physician-assisted suicide (dying), doctor-assisted dying (suicide), and more loosely termed mercy killing, means to take a deliberate action with the express intention of ending a life to relieve intractable (persistent, unstoppable) suffering.
Some interpret euthanasia as the practice of ending a life in a painless manner. Many disagree with this interpretation, because it needs to include a reference to intractable suffering.
In the majority of countries euthanasia or assisted suicide is against the law. According to the National Health Service (NHS), UK, it is illegal to help somebody kill themselves, regardless of circumstances. Assisted suicide, or voluntary euthanasia carries a maximum sentence of 14 years in prison in the UK. In the USA the law varies in some states