perturb vs upset

perturb

verb
  • To disturb; to bother or unsettle. 

  • To modify the motion of a body by exerting a gravitational force. 

  • To modify slightly, such as an equation or value. 

  • To slightly modify the motion of an object. 

upset

verb
  • To disturb, disrupt or adversely alter (something). 

  • To be upset or knocked over. 

  • To shorten (a tire) in the process of resetting, originally by cutting it and hammering on the ends. 

  • To make (a person) angry, distressed, or unhappy. 

  • To tip or overturn (something). 

  • To defeat unexpectedly. 

  • To thicken and shorten, as a heated piece of iron, by hammering on the end. 

adj
  • Angry, distressed, or unhappy. 

  • Feeling unwell, nauseated, or ready to vomit. 

noun
  • An upper set; a subset (X,≤) of a partially ordered set with the property that, if x is in U and x≤y, then y is in U. 

  • The dangerous situation where the flight attitude or airspeed of an aircraft is outside the designed bounds of operation, possibly resulting in loss of control. 

  • An unexpected victory of a competitor or candidate that was not favored to win. 

  • An overturn. 

  • Disturbance or disruption. 

  • An upset stomach. 

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