free as a bird

To be free as a bird means that you are completely and utterly free to do what you want and when you want without having to answer to anyone or worrying about you plan to do. It is a figurative phrase which is aimed at showing that you are free in one way or another whether it be that you are single (not married) and able to come and go as you please or you simply have a free frame of mind allowing you to do things without worrying about the small details.