If the term is used pejoratively, then MUTHEER LIL-FITAN, suggested by Sami, Amer, and Azimof would be the most appropriate term. The person would be described generally as a public menace, a fear mongerer, or one who capitalizes on the polarization of the populace.

On the other hand, "agitator" can also be used in a benign way to describe someone who simply stirs the public interest in certain controversial issues, according to the American Heritage Dictionary. In this case, MUTHEER LIL-FITAN would be inappropriate. I would rather suggest:

محرك لاهتمامات الجمهور
مثير للقضايا العامة
مثير للجدل
مثير للحوار

MUHARRIK LI IHTIMAMAT AL-JUMHOOR
MUTHEER LIL-QADHAYA AL-"AMMA
MUTHEER LLi-JADAL
MUTHEER LIL-HIWAR

etc.


Fuad