palliate vs put at rest

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 at rest

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