When you get rid of something that you do not want or do not like, you take action so that you no longer have it or suffer from it.

If you get rid of someone who is causing problems for you or who you do not like, you do something to prevent them affecting you any more, for example by making them leave.

If you rid a place or person of something undesirable or unwanted, you succeed in removing it completely from that place or person.

If you rid yourself of something you do not want, you take action so that you no longer have it or are no longer affected by it.

If you are rid of someone or something that you did not want or that caused problems for you, they are no longer with you or causing problems for you.

If you say that someone is well rid of someone, you think it is good that the person has gone because you did not like them or you think they caused a lot of problems.