definition euthanasia
Full Definition of EUTHANASIA. : the act or practice of killing or permitting the death of hopelessly sick or injured individuals (as persons or domestic animals) in a relatively painless way for reasons of mercy.â euÂ·thaÂ·naÂ·sic \-zik, -sik\ adjective. See euthanasia defined for English-language learners. the act or practice of killing or permitting the death of hopelessly sick or injured individuals (as persons or domestic animals) in a relatively painless way for reasons of mercy. â euÂ·thaÂ·naÂ·sic \-zik, -sik\ adjective.