Comment by Taraezor Surely someone has worked out a way to post a screenshot of this cool spell! (Edit: As of patch 6.2.3 I haven't received a down vote for this attempt at humour. Haste will lower your GCD, down to a minimum of 1 second.
The simplest way to tell if a spell is GCD free is to just test it yourself (via a target dummy if necessary) - if you can cast a second spell instantly afterwards it's GCD free, if you need to wait a second or so then it isn't. Typically these are abilities specifically designed to be triggered at the same time as second ability, for example on-use trinkets or spells like. Most spells have a 1.5 second GCD, although some classes have a 1 second GCD (i.e. Comment by blupache This is the cooldown that starts whenever you cast a spell, preventing you from casting another spell until its finished.
