Disarming Charm

The Disarming Charm is a defensive spell that aims to disarm an opponent, causing whatever is in the persons hand at the time, usually a wand, to fly out of his or her hand.

It has been known to knock an opponent backwards in some cases. This may depend on whether the spell strikes an opponent's wand or body. The charm's incantation is Expelliarmus.

Etymology
The former half of the word "expelli-" bears resemblance to the Latin "expello" meaning "to drive away, eject or expel" or " to remove or repudiate" (though it may simply derive from the English "[to] expel" also). The latter half "-armus" may directly come from the Latin "armus" meaning "shoulder", "armatura" meaning "armour" or "equipment" or simply the English "arm". In all cases, the combined phrase would read something like to expel equipment from the arms/shoulders, which correlates well with its known effects.

Appearance and effect
The Disarming Charm can vary in its precise effects. Sometimes, it manifests as a "jet of red light", and knocks the victim backwards as well as disarms him or her. This is what happened to Viktor Krum in 1995. On other occasions, the charm does not have a colour, and instead simply makes a wand fly from the victim's hand. When Severus Snape cast the spell on Gilderoy Lockhart, it was shown as a scarlet ring surrounding the wand, with a streak of scarlet light heading towards Lockhart. It may be that the effects are dependant on what it hits - if it hits a wand, the wand is launched, and if it hits a person, the person is launched.

When Cho Chang spoke the incantation incorrectly, Expellimellius, it set her friend Marietta Edgecombe's sleeve on fire. Sometimes when the spell is done weakly but not incorrectly it can make someones hair just stand on end or blow them back a few paces.

Harry Potter's signature spell
"Expelliarmus is a useful spell, Harry, but the Death Eaters seem to think it is your signature move, and I urge you not to let it become so!"

- Remus Lupin discussing the Death Eaters' knowledge of Harry Potter's signature spell

Many people considered the Disarming Charm to be the signature spell of Harry Potter. Despite being taught it by the teacher he despised the most (Severus Snape, until the events of 1997), Harry found it quite useful and utilised it often in direct confrontation with another wizard. He became highly proficient with it in 1994 when practicing for the Triwizard Tournament. At the end of the tournament, after he and Cedric Diggory were transported to the graveyard in Little Hangleton and Cedric was murdered, Harry faced the newly-restored Lord Voldemort in a duel. Voldemort used the Killing Curse and Harry used the Disarming Charm. Due to the natural brotherhood of Harry's wand and Voldemort's wand, both containing cores from the same source (that source being Fawkes, the pet Phoenix of Albus Dumbledore), both duellers' spells proved ineffective, creating the rare Priori Incantatem effect which greatly contributed to Harry's subsequent escape.

Many Death Eaters witnessed this, and took to believing that it was Harry's signature move. In the Battle over Little Whinging, they identified him as the real Harry Potter out of the "seven Potters" once he used the Disarming Charm against the Imperiused Stan Shunpike. Remus Lupin later chided Harry for using Expelliarmus in battle conditions, but Harry continued to value it; his argument being that hitting Stan with a stunning spell, as Lupin had suggested, could have ultimately killed him after falling from such a height. When Voldemort attacked Harry, his wand recognised Voldemort as an enemy, despite the fact that the Dark Lord was using Lucius Malfoy's wand instead of his own in order to avoid causing Priori Incantatem. Harry's wand shot "a spurt of golden fire" at Voldemort, destroying Lucius's wand and allowing Harry and Hagrid to escape to safety.. In his final duel with Voldemort during the Battle of Hogwarts, Harry again used a Disarming Charm against Voldemort's Killing Curse, repeating the event of 1995 with the exception of Priori Incantatem taking place.

Known practitioners

 * Albus Dumbledore
 * Cedric Diggory
 * Cho Chang
 * Colin Creevey
 * Dennis Creevey
 * Draco Malfoy
 * Dumbledore's Army
 * Ernie Macmillan
 * Fred Weasley
 * George Weasley
 * Gilderoy Lockhart
 * Ginny Weasley
 * Harry Potter
 * Hermione Granger
 * James Potter
 * Lord Voldemort
 * Luna Lovegood
 * Neville Longbottom
 * Remus Lupin
 * Ron Weasley
 * Severus Snape
 * Sirius Black
 * Zacharias Smith

Behind the scenes

 * In the Doctor Who episode 'The Shakespeare Code', the spell is mentioned in connection to the Harry Potter books, with the Doctor stating "good ol' JK" after Shakespeare uses the word Expelliarmus to conclude a 'magical' formula to banish the episode's villans, the Carrionites, from Earth.
 * Expelliarmus has a surprising (possibly the highest) number of conflicting portrayals across Harry Potter media. In the Chamber of Secrets and Prisoner of Azkaban video games, Expelliarmus conjures a shield, identical in its effects to the books' Protego (used to repel the opponent's attacks), and does not physically "disarm" the opponent at all, though it is still called the "Disarming Charm". In Order of the Phoenix, Expelliarmus was used to finish (disarm) opponents. It doesn't appear in Philosopher's Stone, and in Goblet of Fire it's only seen in a cutscene and as part of Priori Incantatem. In the Half-Blood Prince video game, it appears as a projectile cloud of blue and violet energy which blasts the victim off their feet, but does not send their wand flying. In Harry Potter and the Deathly Hallows: Part 1 (video game) it acts somewhat like Stupefy, knocking the foe to the ground with a burst of golden light for a short period of time.
 * In the film series, Expelliarmus is used many times. Snape uses it first, at the Duelling Club, blasting Gilderoy Lockhart through the air without actually disarming him which appears as a light golden light. In Prisoner of Azkaban, it regains its official effects, used many times to simply knock the wand from the target's hand which is a blue light without physically assaulting them, except for when used by Harry against Snape, though this could be attributed to Harry using Hermione's wand at the time, a feat which can have unpredictable effects for any wizard.
 * Upon meeting with Severus Snape, Albus Dumbledore used a possible variation of the Disarming Charm, which seemed to utilise the effects with lightning speed.
 * In the book Harry Potter and the Deathly Hallows, the text incorrectly uses the word Disarmed with a capital 'D' in referring to Ron's non-magic grappling of Peter Pettigrew's wand from the latter's grasp at Malfoy Manor: The silver tool that Voldemort had given his most cowardly servant had turned upon its Disarmed and useless owner... (chapter 23). Like other spells and incantations, Disarming is normally capitalised in the books. This error possibly occurred as a result of over-enthusiastic application of this style by the author or publisher during the copy-editing process.
 * Though no mention of a particular hand motion is mentioned in the books, in the films, the caster often twirls his or her wand in a tight spiral motion.

Appearances

 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Chamber of Secrets (film)
 * Harry Potter and the Chamber of Secrets (video game)
 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Prisoner of Azkaban (film)
 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Goblet of Fire (film)
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Order of the Phoenix (film)
 * Harry Potter and the Order of the Phoenix (video game)
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Half-Blood Prince (film)
 * Harry Potter and the Half-Blood Prince (video game)
 * Harry Potter and the Deathly Hallows
 * Harry Potter and the Deathly Hallows: Part 1
 * Harry Potter and the Deathly Hallows: Part 1 (video game)
 * Harry Potter and the Deathly Hallows: Part 2
 * Harry Potter and the Deathly Hallows: Part 2 (video game)
 * Lego Harry Potter Years 1-4
 * Harry Potter: Spells

Notes and references
Expelliarmus Sortilège de Désarmement Aseistariisuntaloitsu Expelliarmus Экспеллиармус