An excuse is a reason which you give in order to explain why something has been done or has not been done, or in order to avoid doing something.

To excuse someone or excuse their behaviour means to provide reasons for their actions, especially when other people disapprove of these actions.

If you excuse someone for something wrong that they have done, you forgive them for it.

If someone is excused from a duty or responsibility, they are told that they do not have to carry it out.

If you excuse yourself, you use a phrase such as 'Excuse me' as a polite way of saying that you are about to leave.

You say 'Excuse me' when you want to politely get someone's attention, especially when you are about to ask them a question.

You use excuse me to apologize to someone when you have disturbed or interrupted them.

You use excuse me or a phrase such as if you'll excuse me as a polite way of indicating that you are about to leave or that you are about to stop talking to someone.

You use excuse me, but to indicate that you are about to disagree with someone.

You say excuse me to apologize when you have bumped into someone, or when you need to move past someone in a crowd.

You say excuse me to apologize when you have done something slightly embarrassing or impolite, such as burping, hiccupping, or sneezing.

You say 'Excuse me?' to show that you want someone to repeat what they have just said.