Re: Islamic Philosopher
Philosophy concerns itself with things like ethics, metaphysics (which deals with the basic nature of things), the limits of knowledge, etc.
Islamic Philosophy, then, is the study of such things from an Islamic perspective, i.e. within accordance to Islamic theology.
Continuation of the line of thought of Greeks. Although it’s not obvious, math and science have their root in philosophy.
Islamic philosophers, such as Al-Ghazali , were heavily influential on European thinking.
Aside from that…do philospohers ever really ‘contribute’ anything except questions? 
There most likely were, although there were no people who practiced philosophy as a rigid discipline…