exasperate vs overstrain

exasperate

verb
  • To tax the patience of; irk, frustrate, vex, provoke, annoy; to make angry. 

overstrain

verb
  • To subject to an excessive demand on strength, resources, abilities, or the imagination. 

noun
  • excessive strain 

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