In dreams, flour can signify hard work and creating something. For example, if you dreamed of using flour to make a pie crust and the crust turned out discolored or burnt, then your hard work was in vain. However, if the pie tasted good, then your hard work was worthwhile. The way in which you use the flour in a dream can be telling of its meaning. If you are working with the dry powdery substance and it gets on your hands and clothes, this could signify that you need to clean up something that is dirty or unkempt in your life such as perhaps some unfinished business.
A person may also dream of flour as a representation of their creative skills, or as a symbol that they are working on some kind of creative project.