Denying

Denying is the act of preventing enemy heroes from getting the last hit on a friendly unit by last hitting the unit yourself. Enemies earn reduced experience if the denied unit is not controlled by a player, and no experience if it is a player controlled unit. Enemies gain no gold from any denied unit. All allied units can be denied once they fall below a certain percentage of health: creeps, non-hero units, and illusions at 50%, heroes at 25%, and towers at 10%.

Denying units
Allied creeps and siege units can be denied once they fall below 50% health. Denying an allied, non-player-controlled unit grants half experience to enemies within a 1300 range. To deny a unit, you must force an attack command on it. (By default this requires you to press 'A' and Left-click on the unit. On a setup with WASD on camera controls the default is space then Left-click on the unit.)

Denying creeps is an excellent way to control a lane and gain a lead over your opponent. It not only prevents them from gaining gold and moves the creep equilibrium towards your tower, it also denies your opponent experience which can cause a noticeable level difference in lane.

Some units such as 's Warlock's Golem and 's Spirit Bear grant a significant gold reward should an enemy hero successfully land the killing blow on them. Denying these units is an excellent way to prevent giving the enemy free gold when the unit is unlikely to survive.

It should be noted that the Necronomicon Warrior does not trigger Last Will on a deny, though this is still a waste of the warrior's utility and is not recommended.

Couriers cannot be denied.

Denying towers
Towers may only be denied once they drop below 10% health, and doing so significantly reduces the global gold reward the enemy team gains from the tower's destruction. The difference between the standard tower bounty and a denied tower's bounty is as follows: Denying a tower also prevents an enemy player from receiving the - bonus gold for the last-hit.

Denying heroes
Heroes can also be denied under specific circumstances. A denied hero prevents the enemy from gaining any experience or gold from the kill, but still loses gold upon death.

A hero under 25% health and under the effects of certain spells can be denied by an allied hero. The three spells that allow allied hero denial are:
 * 's
 * 's
 * 's

During, may be denied in a similar fashion if the sun is below 50% health.

It is possible to deny oneself (commit suicide) in a variety of ways:
 * 's Pocket Deny
 * 's
 * 's
 * 's
 * 's cast on an ally
 * 's cast on an ally

It is also possible to deny allied heroes with some abilities:
 * 's
 * 's affects allies when attempting to deny him, and thus, it can also deny allies who attack him.
 * 's, ' , 's and 's Dominate can be used on an enemy ranged unit that has a projectile attack in flight, and results in the denial of an allied hero if the attack deals the finishing blow.

Lastly, a hero is considered denied if a neutral creep (e.g. Roshan) deals the finishing blow.

Exceptions
Though usually making the last hit on an allied unit counts as a deny, it does not count as one when that ally is under the effect of or. In this case, the kill is credited to the caster of said ability.