Quote from American Heritage Dictionary:

"Compassion; forbearance; charity; benevolence."

Description:

MERCY, a reflection of the Absolute, is a Trump representing the music of the spheres on all levels. The head of the androgyne which centers this Atlantean book is the quaternary symbol of the star; it masks the face. The fire of the spirit is here transformed into the water of grace which streams down from the figure's open hand. In the harmonious instrument behind, the planets rotate as jeweled fruit; their celestial bodies strike a chord of patient restraint in measured time. The Ibis, divine messenger from high consciousness, tops the sparkling tree. As above, so below. Mercy is the graceful intermediary, joining heaven and earth.

Interpreted use:

All is in accordance. Your dearest wish flourishes on earth in grace.

Reversed (card received upside down):

You are playing with fire. Be sure you have enough water.