Rennervate (REN-er-vayt)
"en-" Old French from "in-" L. cause to be + "nerves" Eng. c.1603 strength, from "nervus" L. nerve
See Edits and Changes to the Text - GF; this spell has been officially renamed by JKR from its original name. Some versions list this spell as "Enervate," which changes the etymology quite a bit. In fact, if the word was really Enervate, the Latin origins would have exactly the opposite meaning from what it meant as Ennervate.
Spell used to revive a person who has been hit by a Stunner.
Amos Diggory woke up Winky with this (GF9)
Dumbledore used it to revive Barty Crouch junior (GF35)
Dumbledore also used it to revive Viktor Krum after he was stunned while watching over Barty Crouch senior (GF28).