串通: (暗中勾结, 使彼此语言行动互相配合) gang up; collaborate; collude with; be in collusion with; work hand in glove with; conspire with sb. for illegal acts; conspire with:被告和原告串通。the defendant colluded with
串通作弊: league together for some evil end; be in collusion over corrupt practices; conspire with sb. for illegal acts; conspire to cheat