大动干戈 dàdòng-gāngē
(1) [stage a war]∶干戈:古代两种兵器。指进行战争
(2) [make a big fuss over]∶比喻大张声势地行事
这事很简单,何必大动干戈呢
(3) [take effort to do]∶比喻大费手脚
(4) [attack brutally;strike violently]∶也指大打出手