Waswasa has to be one of my all-time favourite Arabic words. Because it sounds exactly like what it is. It's a demonic, satanic "whisper".

We are taught in the Islamic tradition that not all of your thoughts are your own. In fact, there are four sources of thoughts:

1. Rabbani (Divine) - those thoughts that Allah blesses you with - where you feel suddenly compelled to do something good

2. Malakani (Angelic) - these are beautiful, angelic inspirations. I believe all writers and artists completely depend on these.

3. Shaytani (Satanic) - these are demonic suggestions, or 'waswasa'. ie. Really bad thoughts about doing really bad things.

4. Nafsani (Egoic) - these are compulsive thoughts that come from your own ego.