assailant vs punching bag

assailant

noun
  • Someone who attacks or assails another violently, or criminally. 

  • A hostile critic or opponent. 

adj
  • Assailing; attacking. 

punching bag

noun
  • A person serving as an object of abuse. 

  • A tough bag, usually cylindrical, filled with air, sand, or other material, often suspended so that it swings freely, which is punched or kicked when practising sports such as boxing or martial arts. 

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