Answer:
Empathy is a noun meaning the ability to understand and share the feelings of another.
Sympathy is a noun meaning the of pity and sorrow for someone else's misfortune; an expression of such feelings; condolences; support in the form of shared feelings or opinions; or the agreement with or approval of an opinion or aim; a favorable attitude.
More simply, empathy is the ability to understand; sympathy is an action showing understanding or support.