To scold someone or tell someone that you are angry with them (often after the person has done something wrong). "I told him off." "I let him have it."

This means you are very angry or frustrated with someone, so you speak to them very strongly, maybe you shout at them, so they definitely understand what you think. It might be part of a serious argument with another person. Usually the sentence construction is "I really gave him a piece of my mind." This is the best way to say it, it means you were very strong with what you said to that person and they definitely heard you.