-- Severus Snape disarming Gilderoy Lockhart during Duelling Club, knocking him backwards off the stage (CS11)
"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!”
“I won’t blast people out of my way just because they’re there ... That’s Voldemort’s job.”
-- Remus Lupin and Harry Potter (DH5)
Causes opponent’s weapon to fly out of his or her hand. The opponent is then said to have been Disarmed.
References from the canon
- Basic defensive spell, taught at the Duelling Club by Snape (CS10) used frequently thereafter. If the exact nature of the opponent's weapon is uncertain, the spell can have unexpected results. If several people cast the spell simultaneously, the target may be rendered unconscious (PA19, GF31, GF34)
- Lupin used this on Harry, Ron, and Hermione simultaneously in the Shrieking Shack on the night they first met Sirius Black (PA17).
- Snape's use of this spell against Lockhart had rather violent results (CS10).
- When Harry faced Voldemort in the Little Hangleton Graveyard, the only duelling spell he knew was the Disarming Charm. When he attempted it, the Priori Incantatum, or "Reverse-Wand Effect" happened due to the fact that both his holly wand and Voldemort's yew wand contained "twin-wandcores" of Phoenix feather (GF34)
- This was the first spell taught at the first D.A. meeting. Zacharias Smith thought this was silly, but Harry pointed out that he used that spell against Voldemort just a few months before and that it had saved his life (OP18).
- Harry cast this at Stan Shunpike (DH4).
- Used by Ron against Bellatrix Lestrange at Malfoy Manor (DH23).
- Harry again used this against Voldemort during their final duel (DH36).
- Referred to in verb form Disarm (DH4, DH5, etc.)
"expelo" L. to drive out + "arma" L. weapon
During the Battle of the Seven Potters, Harry used "Expelliarmus" several times, but Lupin later chastised him for not using his "signature spell" instead of something more powerful. But each time Harry made the hero's choice to disarm instead of maim or kill, things worked out for him.