When you see a creature in range casting a spell using verbal, somatic, or material components, you may try to interrupt it with a reaction. The target makes a constitution save. On failure, the spell dissapates, and the the casting action, bonus action or reaction is wasted. If the spell used a spell slot, it's not expended.
The most valuable ability as a professor in the Royal University is not academic excellence, but quick reflexes.
-Eudoria Hackett, Royal professor
Target a creature, object, or magical effect in range and automatically end any ongoing spells of the casting level or lower. For more powerful spells, you must make a spellcasting ability check against DC 10 + the target spell's level, ending it on a success.
The School of Abjuration has the most applications of all the arcane schools, which they were very proud of until they realized most of the applications were from peasants that wanted to learn how to make magic go away.
-Archmage Julian
Create a 10-foot-radius, 20-foot-tall Cylinder of magical energy and glowing runes centered on a grounded point you can see in range.
Choose creature types from Celestials, Elementals, Fey, Fiends, and Undead. The chosen types of creature have significant disadvantages against creatures inside or outside the circle.
The duration of the spell scales by 1 hour per level.
See the Player's Handbook for exact rules.
Catching shrieking devils in magic circles is old Warlock nonsense. We are modern. We catch shrieking embodiments of fire in magic circles.
-Conjurer Kelton Pepperkeep
Break all curses affecting a creature or object. If the target is a cursed magic item, the curse remains, but its owner's attunement is broken.
At the end of the day, curses are weavecraft, so we can undo them with a bit of clever prodding.
-Abjurist Wilvirik Vixtoscien
Conjure a shimmering sphere to enclose a Large or smaller creature or object in range. An unwilling creature may roll a Dexterity save to avoid being enclosed. Absolutely nothing may pass through the barrier, although an enclosed creature may breathe. It is immune to all damage, and no external attacks or spells may affect the creature inside or vice versa.
The globe is perfectly sized to the thing inside it and is weightless. A creature inside may use an Action to roll the sphere at half its speed, and the globe may be picked up and carried by other creatures.
The globe may be destroyed by a Disintegrate spell without damaging anything inside.
Quotation.
-Quote Source