descent vs onfall

descent

noun
  • A falling upon or invasion. 

  • A particular extension of the idea of gluing. 

  • A sloping passage or incline. 

  • A drop to a lower status or condition; decline. 

  • Lineage or hereditary derivation. 

  • An instance of descending; act of coming down. 

  • A way down. 

onfall

noun
  • A falling on or upon; an attack, onset, or assault. 

  • The fall of the evening. 

  • A fall of rain or snow. 

verb
  • To fall on or upon. 

  • To assault, attack. 

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