In languages that derive from Latin, "compasion" means we cannot look on coolly as others suffer, or, we sympathize with those who suffer. Another word with approximately the same meaning, "pity" (Fr. "pitie'", Ital. "piet-", etc.) denotes a certain condescension toward the sufferer. "To take pity on a woman" means that we are better off than she, that we stoop to her level, lower ourselves.
That is why the word "compassion" generally inspires suspicion; it designates an inferior, second-rate sentiment that has little to do with love. To love someone out of compassion means not really to love.
In languages that form the word "compassion" not from the root "suffering" but from the root "feeling", the word is used in approximately the same way, but there is no connotation of condescension, hence no sense that the sentiment is in any way inferior. The secret strength of its etymology floods the word with another light and gives it a broader meaning. To have compassion (co-feeling) means not only to be able to live with the other's misfortune, but also to feel with him any emotion--joy, anxiety, happiness, pain. This kind of compassion (in the sense of soucit, wspcolczucie, Mitgefuhl, medkänsla) therefore signifies the maximal capacity of affective inspiration, the art of emotional telepathy. In the hierarchy of sentiments, then, it is supreme.
-- Milan Kundera (in a superb translation by Michael Henry Heim)