Hedonism locates the good life in pleasure — more of it, less pain. Eudaimonia locates it in virtuous, purposeful activity, where pleasure may accompany a flourishing life but is never the thing that makes it good.
Side by side
Aspect
Eudaimonia
Hedonism
The good is
Flourishing through virtue
Pleasure
Measured in
A whole life's activity
How it feels now
Pleasure is
A by-product
The goal
A hard season
Can still be part of it
Counts against it
What each one means
Eudaimonia
Eudaimonia is the ancient Greek idea of human flourishing — "living well" as the highest good, achieved over a whole life of virtuous, purposeful activity rather than through momentary pleasure or good feeling.
Hedonism names three different things: the value claim that pleasure is the only thing good in itself and pain the only thing bad in itself; the separate psychological claim that pleasure and pain are all that motivate us; and, in everyday use, devotion to pleasure as a way of life.