ㄑㄧㄤˊㄊㄡˊㄘㄠˇqiángtóucǎo

墙头草
  1. 容易搖擺倒伏比喻立場堅定」。 大是大非面前不當牆頭草」。

sb who goes whichever way the wind blows, sb with no mind of one's own, easily swayed person, opportunist