Silence

Silence is a status effect that prevents those affected from using active hero abilities for the duration of the silence. It can be useful when ganking a hero with a blink or invisibility spell, as silences tend to have longer duration than other disables giving more time to kill the enemy. Silences in teamfights can also be very effective even for a short period of time, as they prevent the enemy from using their spells in combination with one another. Silencing an opponent also stops any channeling spells that they are currently using.

Mechanics
When a unit is silenced, the ability icons in its HUD are overlayed by a grid-like effect. Clicking on an active ability or pressing its hotkey displays the word "Silenced" in red on the screen.

Silence disables every active ability, including toggle abilities and active attack modifiers. If an ability is being channeled, silence cancels it immediately. If an ability is toggled on, silence does not turn it off, but prevents the player from toggling it off. If the toggle ability drains mana and the unit runs out of mana while silenced, the ability toggles off normally.

Silence does not stop the effects of already cast spells. For example, silencing after he has already cast  or  does not stop the link from draining or the storm from striking.

Silence does not disable any passive ability. Although silence prevents, for example, from using the active part of, it does not cause the critical to stop proc. Even when a passive ability has a cooldown or mana cost, silence never affects them in any way.

Mute
As a counterpart to silence, a mute disables the affected unit's active items in the same fashion as silence disables active abilities. As with silence, it does not affect passives at all. It does not stop already ongoing effects of items, but does cancel channeled items. It also prevents the unit from toggling their toggle items on or off.

Sources of mute
Besides the listed abilities, non-sharable items are always muted when picked up by a different unit than the owner.