How do you spell Emissary

Available Definitions:
1)  n. - An agent employed to advance, in a covert manner, the interests of his employers; one sent out by any power that is at war with another, to create dissatisfaction among the people of the latter.
2)  a. - Exploring; spying.
3)  a. - Applied to the veins which pass out of the cranium through apertures in its walls.