Attack Speed of Primary skills (Spirit Generators) increases by 15%.
"The harmony of mind, body, and spirit brings many blessings. A monk who has become as one will move like a storm crashing into the mountains. Fast, hard, and without hesitation." — Patriarch Anisim
Alacrity is a Monk passive skill, unlocked at level 40. As of Patch 2.1, it replaced the Guiding Light.
The skill only affects Primary attacks: Fists of Thunder, Deadly Reach, Crippling Wave and Way of the Hundred Fists. Other skills that replenish Spirit do not benefit from it.