blindside vs thwack

blindside

verb
  • To catch off guard; to take by surprise. 

  • To attack (a person) on his or her blind side. 

noun
  • The blindside flanker, a position in rugby union, usually number 6. 

  • A person's weak point. 

  • A tram/train driver's field of blindness around a tram (trolley/streetcar) or a train; the side areas behind the tram/train driver. 

  • The space on the side of the pitch with the shorter distance between the breakdown/set piece and the touchline; compare openside. 

  • A driver's field of blindness around an automobile; the side areas behind the driver. 

thwack

verb
  • To beat. 

  • To hit with a flat implement. 

  • To fill to overflow. 

noun
  • The act of thwacking; a strike or blow, especially with a flat implement. 

  • A heavy slapping sound. 

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