improvement vs setback

improvement

noun
  • Increase; growth; progress; advance. 

  • The act of improving; advancement or growth; a bettering 

  • Something which is improved 

  • Valuable additions or betterments, for example buildings, clearings, drains, fences, etc., on premises. 

  • A useful addition to, or modification of, a machine, manufacture, or composition. 

  • The state of being improved; betterment; advance 

  • The act of making profitable use or application of anything, or the state of being profitably employed; practical application, for example of a doctrine, principle, or theory, stated in a discourse. 

setback

noun
  • An offset to the temperature setting of a thermostat to cover a period when more or less heating is required than usual. 

  • An obstacle, delay, disadvantage, blow (an adverse event which retards or prevents progress towards a desired outcome) 

  • A step-like recession in a wall. 

  • The required distance between a structure and a road. 

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