turn a deaf ear 置若罔闻

“置若罔闻”，汉语成语，意思是放在一边，好像没有听见似的。指不去过问、不理睬（ignore completely，pay no attention to）。与英文习语“turn a deaf ear”意思相近，表示“to ignore someone when they complain or ask for something”。

例句：

过去，他们往往对这种要求置若罔闻。

In the past they've tended to turn a deaf ear to such requests.

他们要求释放人质的呼吁被置若罔闻。

Their appeals to release the hostages fell on deaf ears.