If you dream about the guard, then such dream indicates the smart and clever part of your personality. The dream shows that you are always cautious in your waking life. If you see the guard of the prison, then this dream could point to abilities you are suppressing. Perhaps you should become less strict to yourself look at things easier and do not take life too serious. You are punishing yourself for nothing. You do not need to be perfect at everything you do.
Read more about dreaming of Guard in other dream meanings interpretations.