For those who dont know what Rennervate means, it is a Harry Potter spell which defines my blog.
The Wikipedia(Wikia) Definition:
Rennervate is used to bring unconscious individuals back to consciousness, and as such, can be used for more that victims of the Stunning Spell.
There are limitations on this spell’s effectiveness. When Minerva McGonagall was struck by no less than four Stunners, the concentrated damage was intense enough for her to be hospitalised in St. Mungo’s Hospital for Magical Maladies and Injuries, as a simple counter-spell was not enough. It will also not work against certain kinds of Dark magic, for instance, the effects of the Drink of Despair. As with all magic, Rennervate is useless for resurrecting the deceased.