Bombarda

Bombarda is the wizarding world's go-to door-opener. The incantation borrows from the medieval Latin bombarda — a class of early cannon — and the effect is exactly what the name suggests. Cast at a solid surface, Bombarda produces a sharp, focused explosion at the point of contact. Locks shatter. Hinges snap. The door, generally, ceases to be a door.

Where Confringo is a violent offensive curse and Reducto is a more general demolition spell, Bombarda lands in the middle: classified as a Charm, less aggressive than its cursed neighbors, and primarily used for clearing physical obstacles rather than fighting people. Hogwarts students learn to think of it as the spell to reach for when a corridor, a sealed door, or a stuck portrait blocks the way.

The advanced variant, Bombarda Maxima, scales the blast radius dramatically. Where the basic charm puts a hole in a door, Maxima can bring down a wall or even a small building. Hermione's instinctive Bombarda Maxima during the rescue scene in the third film is the version most readers picture, although the books mention it in passing rather than dwelling on it. Death Eaters have been known to use Maxima in the field for breaching wards and forcing entry.

Used responsibly, Bombarda is one of the more polite offensive spells in the curriculum — a problem-solving tool more than a duelling tool, with a clear best use case (locked doors) and a higher version held in reserve for serious obstacles. Used carelessly, it will collapse the room you are standing in.