A coastal structure built to protect a harbor or shore from waves. 防波堤 is the everyday term; 'mole' is a less common English synonym for a massive breakwater.
A long breakwater was built outside the harbor.
Many people also take walks on the breakwater.
They built a breakwater at the harbor entrance.
Large waves were crashing against the breakwater.
That law serves as a bulwark against fraudulent transactions.