What is Mercy?

I've been thinking of the word "mercy" these past few weeks. Last night I was doing some studying of the word and came across this thought. It really touched my heart and gave me a new definition to the word. The best explanation I ever heard was in relation to grace. I was once told that grace is receiving something you don't deserve and mercy is not receiving something that you do deserve. What are your thoughts on this subject? I'd love to hear your feedback.