dispiriting vs oppressive

dispiriting

adj
  • Lowering the morale of; making despondent or depressive; disheartening. 

oppressive

adj
  • Burdensome or difficult to bear. 

  • Hot and humid of the weather. 

  • Tyrannical or exercising unjust power. 

  • Weighing heavily on the spirit; intense, or overwhelming 

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