Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
controversial [kɔntrəˈvəːʃl] adj (topic etc) спо́рный*спо́рен (person, writer) неоднозна́чный*неоднозна́чен
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.