(metaphor) grass growing atop a wall that sways with the wind; refers to a person who has no principles, is easily swayed, or sits on the fence for their own gain

A person with no fixed principles or position who sways with whichever side is currently more powerful; often used in the phrase [[风吹墙头草，两边倒|風吹牆頭草，兩邊倒|feng1 chui1 qiang2 tou2 cao3 liang3 bian1 dao3]].

a person who wavers between two sides and follows whoever is in power at the moment; literally grass on top of a wall sways as the wind blows