1. obstructionist, obstructor, obstructer, resister, thwarter - someone who systematically obstructs some action that others want to take
   --₁ is a kind of disputant, controversialist, eristic
   --₁ has particulars: naysayer; stonewaller
   

   Derived form: verb thwart1

Thwarter

noun

1. a person or thing that thwarts or prevents something
• The detective was praised as a skilled thwarter of criminal operations.
2. (informal) a talented athlete or competitor who consistently defeats opponents
• John is a thwarter on the tennis court; he rarely loses a match.

adjective

• The thwarter employee always finds a way to hinder progress on the project.

verb

1. to frustrate or obstruct the efforts, plans, or desires of someone
• The unruly crowd tried to thwarter the politician's speech by loudly booing.