blank out vs obnubilate

blank out

verb
  • To become blank. 

  • To set even; to neutralise. 

  • To erase (something), leaving a blank in its place. 

  • To temporarily lose memory. 

  • To erase from one's memory. 

obnubilate

verb
  • To make cloudy. 

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