Roughly "intentional nonconsensual interaction which results in the intended outcome of the death of a sentient".

To define how I use 'nonconsensual', I need to describe an entire ethics. Rough summary: Only every action which is performed without the consent of one or more sentient participant(s) is immoral. (Consent need not be explicit in all cases, especially trivial and critical cases; wearing a military uniform identifies an individual as a soldier, and constitutes clearly communicating consent to be involved in all military actions initiated by enemy soldiers.)