If you describe someone's behaviour as unrelenting, you mean that they are continuing to do something in a very determined way, often without caring whether they hurt or embarrass other people.
She established her authority with unrelenting thoroughness.
她坚定地树立起自己的绝对权威。
If you describe something unpleasant as unrelenting, you mean that it continues without stopping.
an unrelenting downpour of rain.
一场下个不停的倾盆大雨。