I am making homemade cupcakes. For the icing my recipe says that I need confectioners sugar. I already know that I can make my own, but i don't want to right now. Can I substitute the confectioners sugar with powdered sugar?
Confectioner's sugar and powdered sugar are two names for the same thing, at least in US usage. In the UK, this product would be called icing sugar.
So it is not even a substitution, it is the requested ingredient, and of course you can use it by either name.