feud
n long and bitter quarrel between two people, families or groups (两人、 家族或团体间的)长期不和, 世仇
a long-standing feud 夙怨
Because of a family feud, he never spoke to his wife's parents for years. 由於两家不和, 他已多年不与岳父母说话. feud, v [I, Ipr]
~ (with sb/sth) carry on a feud 长期争斗; 结世仇
feuding neighbours 长期不睦的邻居
The two tribes are always feuding (with each other). 这两个部落一直争斗不休.
I suggest that we ask users of this machine what they think about it. We can photograph them using it too. Then we can put their comments at the top of the advertisement in big print. We can bring in some humour too. People enjoy reading humorous ads.