beat off vs self-abuse

beat off

verb
  • To waste time. 

  • To drive something away with blows or military force. 

  • To masturbate, usually a man of himself. 

self-abuse

verb
  • To harm oneself. 

noun
  • Physical or verbal maltreatment of oneself. 

  • Injury inflicted deliberately upon oneself, especially resulting from a mental disorder. 

How often have the words beat off and self-abuse occurred in a corpus of books? (source: Google Ngram Viewer )