The only spell for which he had real ability was the Memory Charm, which he had been using repeatedly for years. His classes quickly became a charade, as he was revealed to be completely inept at everything in which he claimed, in his books, to be expert.
Gilderoy Lockhart focused his considerable talents solely on the Memory Charm until he perfected it, making it the only spell he can perform without fail.
Brackium Emendo is a healing charm. It is supposed to mend broken bones, Alas, Gilderoy Lockhart's magical abilities, or lack thereof, made it so poor Harry's bones vanished instead.
It was Snape who taught Harry his signature spell: Expelliarmus. During Duelling Club in Harry's second year, Snape used the Disarming Charm against Lockhart.
If the spell is strong enough then it may knock someone off their feet. I think J.K. Rowling just wanted to show how weak Lockhart really was (and possibly how powerful Snape was). edit: also Snape would have a lot of emotion behind his spell as he didn't like Lockhart.
The incantation for a Memory Charm was Obliviate, which seems quite fitting for Professor Gilderoy Lockhart, given how (seemingly) oblivious he was to his own shortcomings.
Malfoy spots Harry and casts a Cruciatus curse; Harry, defending himself, using the Half-Blood Prince's Sectumsempra spell without knowing its effects. To his horror, it gashes Draco's face and chest, spilling his blood everywhere.
Salvio Hexia is a defensive spell which presumably deflects hexes from the area. The caster must move their wand in a downwards direction in the opposite direction of their outward hand. The spell must be cast multiple times around an area to be successfully set to defend.
Lockhart's past habit of using the "Obliviate" Memory Charm would cause him the most harm. His own memory was tragically stolen from him. This happens when he attempts to erase Ron and Harry's memories with Ron's damaged wand. Because the wand was damaged, the spell backfired and hit Professor Lockhart instead.
A Memory Charm (also known as Lockhart Memory Charm or Forgetfulness Charm) is a spell that can be used to erase memories from an individual's mind. The incantation for this charm is Obliviate. It is different from the charm that creates false memories.
All of you remember the charming yet silly teacher for Defense against Dark Arts : he was beyond contest the most vain professor that Hogwarts ever welcomed.
The killing curse Avada kedavra is obviously the most powerful one. It was used to kill the most important characters - Harry's parents, Sirius, and Dumbledore. They died instantly without any struggle and also without any scope of survival.
Harry Potter's use on Draco Malfoy in the Duelling Club. The Tickling Charm (Rictusempra), also known as the Rictusempra Charm, is a spell that causes a victim to buckle with laughter. It also has at least two other side effects on the victim. It is usually used as a diversionary tactic in duels.
The Muffliato Charm (Muffliato) was a charm used to fill the ears of any person in the vicinity of the caster with an unidentifiable buzzing sound so as to allow for conversation without being overheard, similar to the Imperturbable Charm.
Arania Exumai was a charm used to blast away Acromantulas or other large spiders. If the spell missed and struck a stone, it would produce a large black scorch mark, and thus was not recommended for use on humans, although casting through or along a human produced no ill effect so long as a spider was struck.
Instead he gave an almightly belch and several slugs dribbled out of his mouth on to his lap. Ron curses himself. The Slug-Vomiting Charm (Slugulus Eructo) is a charm that causes the victim to burp up slugs and slime for approximately ten minutes; they may also take on a sallow complexion as a side-effect.
Sectumsempra is a curse invented by Professor Severus Snape, during his childhood, when he was known as "The Half-Blood Prince". He created it with the intention of using it against his enemies, and it soon became one of his specialties.
The Disarming Charm became Harry Potter's signature spell, and it notably caused the final defeat of Lord Voldemort during the Battle of Hogwarts by rebounding his Killing Curse, because the Elder Wand recognised Harry as its master through the spell connection, and thus strengthened the Disarming Charm to the point ...
In the film adaptation of Harry Potter and the Order of the Phoenix, only Ginny casts the Reductor Curse to smash the shelves in the Hall of Prophecy, instead of every D.A. member present.
But when Ron and Hermione are about to die by Nagini, Ron casts the killing curse as a last resort and it simply rebounds off Nagini as it was nothing.
After the conclusion of the Second Wizarding War, Hermione sought out her parents and returned their memories. They presumably then returned to England.
