If people or things are sundered, they are separated or split by something. The city is being sundered by racial tension Police moved in to separate the two groups, already sundered by distrust. to break something into parts, especially violently = split
To disunite in almost any manner, either by rending, cutting, or breaking; to part; to put or keep apart; to separate; to divide; to sever; as, to sunder a rope; to sunder a limb; to sunder friends