Wilful killing describes the intentional and unlawful causing of another person’s death, typically involving a deliberate act rather than accident or negligence. In practice across England and Wales, Scotland, Northern Ireland and Ireland, it is most commonly used as a descriptive term covering conduct that constitutes murder or, in some contexts, the most serious forms of manslaughter or culpable homicide.The expression “wilful killing” is not itself the primary statutory label for homicide offences, but appears in legislation (for example, in war crimes, international criminal law, and human rights instruments) and in case law when distinguishing intentional killing from reckless or negligent killing. It is also used in inquest, coronial and fatal accident proceedings, and in human rights litigation (e.g. Article 2 ECHR) when assessing whether state agents or others intentionally caused death.Key legal features are intention to kill (or, in some contexts, to cause really serious harm) and absence of lawful justification, such as self-defence. Usage and underlying concepts are broadly consistent across the UK and Ireland, though specific offence labels and statutory frameworks differ by jurisdiction.