obstructor obstructor /əb'strʌktər/

noun

1. Any structure that makes progress difficult  ( impediment , impedimenta , obstructer , obstruction , obstructor )
   any structure that makes progress difficult
     The fallen tree served as an obstruction on the hiking trail.
   The fallen tree served as an obstruction on the hiking trail.
   
2. Someone who systematically obstructs some action that others want to take  ( obstructer , obstructionist , obstructor , resister , thwarter )
   someone who systematically obstructs some action that others want to take