An interrupt is any action that prevents a foe from completing its current action. Skills which are interrupted have a 5 second cooldown before they can be cast again. Chains are reset to the first skill in the chain any time the player is interrupted. Skill activation can be cancelled by a player casting the skill, but is not considered interruption. When an interrupt occurs, the word Interrupt! appears on the screen.
 Effects causing interruption
Most interrupts are caused by control effects. As such, the stability boon provides immunity against interrupts.
- Daze – Disables all skills for a short duration.
- Fear – Disables all skills and causes the target to flee directly away from the caster for a short duration.
- Knockdown – Knocks the target on ground, preventing movement and actions for a short duration.
- Launch – Throws the target in the air over a short distance, preventing movement and actions for a short duration.
- Pull – Pulls the caster to the target or the target to a specific location and disables them for a second.
- Push – Pushes the target away and on the ground, preventing movement and actions.
- Stun – Prevents movement and actions for a short duration.
- Float - Causes the underwater target to move upwards.
- Sink - Causes the underwater target to move downwards.
 Traits that trigger on interrupt
- Interrupts as they existed in Guild Wars (see here) are not as prevalent in Guild Wars 2 because of their dependence on low network latency to be used effectively.
- ^ http://gw2.mondespersistants.com/?article=171&page_art=2 Mondes Persistants interviews Izzy on GW2 PvP