1. to move back and forth or side to side in an erratic, unpredictable manner without clear pattern or control
The drunk man swayed unpredictably as he walked down the street.
O homem bêbado balançava de forma imprevisível enquanto caminhava pela rua.
2. to influence or persuade in an inconsistent or unreliable way
His opinions sway unpredictably depending on who he is talking to.
Suas opiniões oscilam de forma imprevisível dependendo de com quem ele está falando.