ablate vs slack off

ablate

verb
  • To remove or decrease something by cutting, erosion, melting, evaporation, or vaporization. 

  • To undergo ablation; to become melted or evaporated and removed at a high temperature. 

slack off

verb
  • To decrease in intensity; to ease off; to diminish; to die down. 

  • To be deliberately unproductive in one's work or study. 

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