Nutcup is another shiny MMORPG concept strongly tied to politics. In Clan Discussion sub-forum there's always a thread about some clans who have nutcupped and that, my friends, is one of the worst sins in the e-bible of videogaming. Why? Well, I guess people sometimes think that every videogame should be perfectly balanced in each and every aspect so it can be a nice e-sport where you can show your true gaming skills. In most sandbox MMORPG that's just not the case, mainly because players have more freedom and options. In Darkfall city A might be easier to defend than city B but you're free to bring as many soldiers as you want to conquer it and so can do the defending side.
A nutcup is just a bad word to say alliance. Unfortunately, clans doesn't have many tools to wage war on other clans so when your target allies with 5 other clans making the victory impossible, you can't sabotage those quick allies or compromise their trade routes or whatever, the only thing you can do is go to forums and call them cowards and nutcuppers for not giving you a fair fight when Darkfall IS NOT about fair fights.