党同伐异（黨同伐異）　

◎ 党同伐异 dǎngtóng-fáyì

[defend those who being to one‘s own faction and attak those who don‘t;unite only with those of the same ideas and attack the others] 拉帮结派,偏袒同党,攻击异己

原指学术上的派别之间的斗争,后泛指一切集团之间的斗争

党同伐异,此姘彼丑。——周邦彦《汴都赋》