物以类聚wù yǐ lèi jù同类的东西常聚在一起,现在多指坏人跟坏人常凑在一起{like attracts like; birds of a feather flock together, usu. referring to evil persons}: ～,人以群分。{things of a kind come together, people of a mind fall into the same group; like attracts like; birds of a feather flock together}