After checking multiple sources around the internet. We have come to the following conclusion… Everyone is just as confused. 🙂
From what we gather, makeup (no dash) refers to the products we use. Any type of cosmetics involving the face could be referred to as makeup. You will likely see both variations of the word used freely.
The term make-up refers to professional applying makeup. For instance, we here at hawaiimakeupartist.com are actually make-up artists and not makeup artists. By that logic, I guess we should be using hawaiimake-upartist.com and not the one we have. Make-up Artist Magazine uses the dash while other publications do not.
Below are 2 examples of publications doing the opposite of what we just explained. :/
If you have an official take on the two variations we would love to hear from you.