If your first response to Far from the Madding Crowd was "WTF is madding?" rest assured. You're not the first person to be confused.
Hardy borrows this phrase from a famous poem by Thomas Grey titled "Elegy Written in a Country Churchyard." In this context the word "madding" means "frenzied" or "crazed." In other words, Hardy seems to be suggesting that the country is way better than the city because it takes you away from all the hustle and bustle of the crazy city crowds.
Ha! This is totally a sarcastic title. After all, the story's main characters all live in the pleasant countryside and their lives are still filled with drama and anguish. Hardy is suggesting that it's silly to think that life is somehow simpler in the countryside. For Hardy, humans are humans no matter where you go, and there are always just as many problems for country people as there are for city folk.