euthanasier bedeutet auf Englisch

euthanize▼◼◼◼(submit (a person or an animal) to euthanasia)
verb
[UK: ˈjuː.θə.ˌnaɪz] [US: ˈjuː.θə.ˌnaɪz]My vet recommended euthanizing my dog. = Mon vétérinaire m'a recommandé d'euthanasier mon chien.

destroy [destroyed, destroying, destroys]▼◼◻◻(to put down or euthanize (e.g. an animal))
verb
[UK: dɪˈstro.ɪ] [US: də.ˌstrɔɪ]

euthanize▼◼◼◼(submit (a person or an animal) to euthanasia)
verb
[UK: ˈjuː.θə.ˌnaɪz] [US: ˈjuː.θə.ˌnaɪz]