COUNTERSPELL - Abjuration - 3rd Level

Casting Time: 1 Reaction, which you take when you see a creature within 60 feet of you casting a spell.
Range: 60 feet
Components: S
​Duration: Instantaneous

  You attempt to interrupt a creature in the process of casting a spell.  If the creature is casting a spell of 3rd level or lower, its spell fails and has no effect.  If it is casting a spell of 4th level or higher, make an ability check using your spellcasting ability.  The DC equals 10 + the spell's level.  On a success, the creature's spell fails and has no effect.

At Higher Levels: when you cast this spell using a spell slot of 4th or higher, the interrupted spell has no effect if its level is less than or equal to the level of the spell slot used.

Source: 5th Edition SRD, Player's Handbook
Class List: Sorcerer, Warlock, Wizard.