Skill denial

Skill Denial refers to the technique of preventing a foe from using a skill. Skill denial is more direct than Energy denial and less twitchy than Interrupts. Disabling one critical skill can invalidate an opponent's build.

Skills used for this technique include:
 * Arcane Larceny & Arcane Thievery - These spells will disable one random spell for up to half a minute and enable you to use it against the enemy. The disabling effect is good on its own, but the spell steal will be usually useless, since you probably won't have any points in the stolen spell's attribute to use it efficiently.
 * Blackout - In PvE, great on a single enemy rather than a group, while the rest of your team focuses on dealing damage. It may be used to shut down the most dangerous enemy, but leaves you shut down as well.
 * Complicate - This interrupt disables all signets on target foe, so it's good if that enemy focuses on them.
 * Diversion - "Disables" one skill for about 45 seconds, which works great on spammed skills or skills that are critical to the enemy's survival.
 * Ignorance - Another anti-signet skill, this one however doesn't require the user to interrupt a signet.
 * Power Block - This interrupt is devastating against enemies who use spells from just one attribute, like Elementalists focused on one element, healing/protection Monks, and so on.
 * Simple Thievery - Disables and steals only non-spell skills, so it's good against non-casters like Rangers, Warriors, Paragons, and especially Assassins. This is pretty much an anti-warrior version of Arcane Thievery. Using this skill on spellcasters is also a quite reliable way to steal his Resurrection Signet, as it will often be the only non-spell skill on his skillbar.
 * Signet of Humility - Good against a foe that relies on his elite skill to be effective.