Colloportus(MP: 5, Cost: 4 sp)
This spell will magically lock a door, preventing it from being opened for a presumably limited amount of time. It is easily countered by Alohomora, however. The word is a combination of "colligare" (Latin for "bind together"
or Greek kollaō = "I glue or cement or weld", and "porta" (Latin for "door"
. Used in Order of the Phoenix when Hermione needs to seal a door in the Department of Mysteries against some Death Eaters. The fact that the Death Eaters did not just open the doors with Alohomora may indicate complications.
Deletrius (MP: 5, Cost: 4 sp)
Erases images. First seen in Goblet of Fire when Amos Diggory gets rid of the echo of the Dark Mark from Harry's wand.
Densaugeo (MP: 5, Cost: 3 sp)
Makes the victim's teeth grow rapidly. Introduced in Goblet of Fire when Draco Malfoy attacked Hermione outside of the Potions classroom. "Dens" is a Latin noun and means "tooth". "Augeo" is a Latin verb and means "I grow" (from the infinitive "augere" which means "to grow"
.
Diffindo (MP: 10, Cost: 5 sp)
Severs the target. In Goblet of Fire when Harry urgently wants to talk to Cedric Diggory he casts this spell to rip his bag, thus delaying him for class. Harry also tried to use it in Order of the Phoenix to save Ron from the brains in the Department of Mysteries, and also in Half-Blood Prince when he wanted to switch the cover of the Half-Blood Prince's copy of Advanced Potion-Making for a new one, in order to fool Professor Snape. Ron also uses this spell to trim the lace off of his dress robes in Goblet of Fire.
In the Chamber of Secrets videogame, it is mentioned that Diffindo cuts (or severs) things that are organic (carbon-based) in material.
Engorgio(MP: 10, Cost: 5 sp)
Makes something grow larger. Seen in Goblet of Fire when the impostor Professor Moody casts it on a spider to enhance a demonstration of the effects of a Cruciatus Curse. Hagrid is also suspected of performing the charm on his pumpkins once.
Ennervate(MP: 10, Cost: 10 sp)
The counterspell to the Stunning Spell. In Goblet of Fire, Amos Diggory uses it to wake up Winky, while later on Professor Dumbledore uses it to wake up Viktor Krum. In Half-Blood Prince, Harry uses it in an attempt to wake Professor Dumbledore. Maybe more than a counterspell, there have been instances when it is used to help people regain consciousness who haven't been Stupefied. The etymological root of this spell is from Latin for "to add nerve"; hence the English word "ennervate". If spelled with one "n," however, it has the opposite meaning - to weaken, rather than invigorate (though a post hoc explanation could be fashioned to claim that it is the stunning spell that is weakened by this spell, in which case the etymology would fit).
Episkey (MP: 10, Cost: 10 sp)
Used in Goblet of Fire after the first task of the Triwizard Tournament. Nymphadora Tonks uses this spell in Half-Blood Prince to fix Harry's broken nose, later Harry uses it to heal a fat lip. This leads the reader to the conclusion that it is a spell to heal minor injuries (assuming a broken nose is considered a mild injury). The word comes from the Greek "episkevi" ("επισκευή"
, which means "repair". J. K. Rowling writes in Half-Blood Prince, Harry's knowledge tells him that this spell could belong to a family (or variety) of Healing Spells, in the same way a species of plants belongs to a larger genus.
Evanesco(MP: 10, Cost: 10 sp)
Makes something vanish. Used in Order of the Phoenix when Snape makes Harry's Draught of Peace disappear from his cauldron. Also used in Chamber of Secrets when Snape makes the snake disappear. In Order of the Phoenix, this spell is used to make Bill's scrolls on the kitchen table vanish. It is presumed that whatever is Vanished can be made to reappear - surely Bill didn't want his scrolls to disappear completely.
Sorry I took this long 