Stark-mad is an informal way of saying that someone is completely insane or crazy. Although it is a commonly used term, there are several other synonyms that can be used to describe someone who is stark-mad. Some of these synonyms include deranged, unhinged, mentally ill, insane, lunatic, psychotic, and crazy. Each of these terms carries a different connotation and degree of severity, but they all refer to someone experiencing a severe form of mental illness or instability. It is important to remember that mental illness is a serious issue and should be treated with sensitivity and understanding.