The term "mercy stroke" refers to the act of taking someone's life to end their suffering or ease their pain. It's a highly controversial and ethically complex issue but there are other synonyms or phrases that could help clarify or elaborate the concept. These can include "assisted suicide," "end-of-life care," "compassionate killing," "euthanasia," and "painless death." While some may view these terms as euphemisms or outright euphoric, their purpose is to steer away from negative and judgmental language and convey the idea that there are different choices and options when it comes to facing physical and emotional agony.