I totally get that Islam and Muslim (and even the antiquated term 'Mohammedism') are basically the same thing - they refer to the religion and culture based on the teachings of the Prophet beginning in 622AD. I also understand that "Islam" means 'submission,' reflective of the fact that Muslims (or is that those of the Islamic faith?) are to be submitted to Allah.
That said, as any good programmer knows, terms have precise meanings, and even words that are 99% synonymous have correct and distinct usages.
So, in what situations is it correct to use "Islam / Islamic" viz a viz "Muslim?" Is one cultural and the other theological? Or, is one term preferred in certain regions over against the other?