constrict vs obstruct

constrict

verb
  • To limit or restrict. 

  • To narrow, especially by application of pressure. 

  • To coil around (prey) in order to asphyxiate it. 

obstruct

verb
  • To impede, retard, or interfere with; hinder. 

  • To get in the way of so as to hide from sight. 

  • To block or fill (a passage) with obstacles or an obstacle. See synonyms at block. 

How often have the words constrict and obstruct occurred in a corpus of books? (source: Google Ngram Viewer )