First-degree murder is a serious crime that involves the intentional and premeditated killing of another person. This means that the perpetrator planned the murder ahead of time, demonstrating a clear intent to cause death. It is often considered the most severe form of homicide and carries significant legal penalties. In many jurisdictions, first-degree murder can result in life imprisonment or even the death penalty. Factors such as the use of a weapon, the victim's vulnerability, or the presence of aggravating circumstances can influence the severity of the charges. Legal definitions and consequences may vary by state or country, affecting cases involving homicide and criminal law.