English to English

noun (n)

• someone who systematically obstructs some action that others want to take(noun.person)

  Synonym:
  obstructer, obstructionist, resister, thwarter
  

  source: wordnet30
• any structure that makes progress difficult(noun.artifact)

  Synonym:
  impediment, impedimenta, obstructer, obstruction
  

  source: wordnet30