palliate vs put behind one

palliate

verb
  • To cover or disguise the seriousness of (a mistake, offence etc.) by excuses and apologies. 

  • To relieve the symptoms of; to ameliorate. 

  • To placate or mollify. 

put behind one

verb
  • To try to forget (a past negative experience). 

How often have the words palliate and put behind one occurred in a corpus of books? (source: Google Ngram Viewer )