Crowd control

Crowd Control or CC, is the term used to describe a spell or ability that temporarily reduces a unit's ability to affect a fight. Abilities with CC effectively lower the number of opponents that must be dealt with in skirmishes, and shrewd use of crowd control can heavily swing team fights in your favor. This is because crowd control can disable threats or make escape difficult for opponents, both of which make focus fire much easier. The presence of crowd control abilities may make difficult situations perfectly viable to survive, or even save team members whilst killing opponents.

Fundamental Types
There are three fundamentally different categories of crowd control, with most specific forms of CC falling under one or more of them.
 * Movement Modifiers restrict or reduce the target's movement or force a particular move.
 * Slows, Snares, Knockbacks
 * Action Modifiers restrict the target's ability to perform some actions or reduce those actions' effectiveness.
 * Blinds, Silences, Stuns, Knockups
 * Forced Action Modifiers force the target to take a certain action.
 * Taunts, Fears

Specific Types
These are the specific types of crowd control that appear in League of Legends along with a few key notes about each.
 * Slow
 * Reduces movement speed.
 * Snare
 * Immobilizes to prevent movement entirely.
 * Knockback
 * Pushes one or more units to a different spot against their will.
 * Will interrupt channeled abilities.
 * Knockup
 * Knocks the target into the air but does not change their location.
 * Prevents movement, auto attacks, and the use of abilities while in the air.
 * Will interrupt channeled abilities.
 * Blind
 * Makes the target always miss with auto attacks.
 * Has no effects on abilities and will not interrupt them or prevent their damage.
 * Stun
 * Immobilizes and prevents actions.
 * Will interrupt channeled abilities.
 * Blocks use of most abilities.
 * Silence
 * Prevents use of most spells and abilities.
 * Does not stop auto attacks.
 * Will interrupt channeled abilities.
 * Taunt
 * Forces the target to auto attack the taunting champion.
 * This will cause tower aggro on the target.
 * Will interrupt channeled abilities.
 * Can force movement because target will chase to try to autoattack while taunting.
 * Fear
 * Forces the target to run around randomly.
 * Prevents controlled movement, auto attacks, and the use of abilities.
 * Will interrupted channeled abilities.
 * Suppression
 * Prevents movement and nearly all actions.
 * Will interrupted channeled abilities.
 * Is the only CC that cannot be removed by.

Preventing

 * will prevent the application of CC but will not remove it if it's already been applied.
 * The passive on can block the application of CC.
 * can block the application of CC.
 * will block the application of every CC.

Removing

 * The summoner spell removes all CC except suppression.
 * The active on removes all forms of CC including suppression.
 * removes all forms of CC including suppression.
 * ( ult Nether Grasp will continue to do damage.)

Reducing
Note: Duration reduction has no effect on suppression.
 * reduces the duration of CC by 35%.
 * reduces the duration of CC while active by (15/20/25/30/35)%.
 * reduces the duration of CC by (10/25/40)% for (1/2/3) nearby enemy champion(s).
 * reduces the duration of CC while active by (20/25/30/35/40)%.

Movement Modifiers
The ability to either slow opponents down or speed allies up is crucial to landing killing blows in a large majority of cases. Clearly, smart opponents do not want to die so they will attempt to retreat whenever they realise a combat situation is not going favourably. Using CC that provide snares, slows or stuns against retreating opponents will in most cases reward your team with another kill. Alternatively, you could use CC to improve your own movement speed.

Forced Movement
Forced movement crowd control causes the target to move to a different location. This can be in the form of a push (knockback) or a pull. Forced movement can be very powerful control as it can bring a target to your team where it can be killed or further controlled. These abilities can also protect allies by moving enemies away from them.

Action Modifiers
Action modifiers (more commonly known as disables) prevent or reduce the effectiveness of actions the afflicted unit can take. By blinding a melee DPS champion, you are preventing him/her from dealing damage. Other champions, particularly casters, rely on their abilities extensively in combat. Preventing these abilities from being activated will effectively render those champions useless.

Note: Abilities which reduce attack speed are intentionally left out of this list due to how much is already listed. To see those, please refer to Attack Speed.

Forced Action Modifiers
The rarest form of CC, but equally powerful, are the forced action modifiers. These force the target to do something, temporarily rendering the player's input useless.

Suppression
The "ultimate" form of CC. Suppression applies a stun to the target, and disables the use of Summoner spells while ignoring any CC reduction effects.