Eudaimonia and happiness are often thought of as synonyms, but this is a clear and common misconception. Happiness only makes up a piece of eudaimonia. Only after a life of happiness will one achieve a state of eudaimonia, or the ultimate good, which is only determined after death. Eudaimonia is also often compared to hedonism, but, again, this is a misunderstanding. Hedonism is self centered, focusing on the the attainment of brief satisfaction through material and physical things, while eudaimonia is other centered, emphasising life fulfillment. Directly translated from Ancient Greek, Eudaimonia means "good spirit" ("eu" meaning "good" and "daimōn" meaning "spirit,") but Aristotle more often interprets the word as "flourishing." .
To live a life of eudaimonia, our happiness cannot be fleeting; it has to be a constant and continuous element of our lives. However, a person cannot flourish by just holding happiness within them. To reach eudaimonia, one must not only be embodied with virtue, but also act upon it. Aristotle said, "for the state of mind may exist without producing any good result, as in a man who is asleep or in some other way quite inactive, but the activity cannot; for one who has the activity will of necessity be acting, and acting well." This alone sets eudaimonia apart from all components of happiness because it pairs an emotion with an action. .
However, Aristotle defines eudaimonia with no general rules. Aristotle states in book I chapter 3 that the "discussion will be adequate if it has as much clearness as the subject-matter admits of, for precision is not to be sought for alike in all discussions, any more than in all the products of the crafts. Now fine and just actions, which political science investigates, admit of much variety and fluctuation of opinion, so that they may be thought to exist only by convention, and not by nature.