headbanger vs mad person

headbanger

noun
  • A mad or eccentric person. 

  • One who dances by violently shaking the head in time to the music. 

  • A kind of chin-up or pull-up exercise where the head is kept in line with the bar. 

  • One who enjoys heavy metal (rock) music, to which this sort of dance is usually performed. 

mad person

noun
  • insane, mentally deranged person 

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