The killing of a dog, chiefly where the death is not in the best interests of a dog. A veterinary surgeon who gave a lethal injection to kill a dog in pain would not be committing cananicide.
You put your clean linen on the washing line outside to dry, only to find your dog later has pulled it down, and it is filthy and needs to be washed. You are furious with the dog, kill it and you have committed cananicide.
Thoughts of cananicide are common amongst owners of "canine menaces" and those who loathe dogs.