Source : Webster's Revised Unabridged Dictionary (1913)

Obstructionist \Ob*struc"tion*ist\, n.
   One who hinders progress; one who obstructs business, as in a
   legislative body. -- a. Of or pertaining to obstructionists.
   [Recent]

Source : WordNet®

obstructionist
     n : someone who systematically obstructs some action that others
         want to take [syn: {obstructor}, {obstructer}, {resister},
          {thwarter}]