* πάλι (páli): This is the most common and versatile translation for "again." It works in most situations where you'd use "again" in English.
* ξανά (xaná): This is another common word meaning "again," often used interchangeably with *πάλι*. Some might say *ξανά* has a slightly more emphatic feel.
* επανα- (epana-): This is a prefix meaning "again," "re-," or "anew." It's not a word on its own but is used to form many words like επαναλαμβάνω (epanalambánō - to repeat) or επανερχομαι (epanerchomai - to return).
* ακόμα (akóma): This word means "still," "yet," or "also," but can sometimes be used to mean "again" in specific contexts, particularly implying a continuation of an action. For example, "Let's do it again" could be translated using this if the emphasis is on continuing the activity.
Therefore, the best Greek word for "again" depends heavily on the sentence. In most cases, πάλι (páli) or ξανά (xaná) will be appropriate.