becloud vs mist up

becloud

verb
  • To cover or surround with clouds. 

  • To cast in a negative light, cast a pall over, darken. 

  • To cause to become obscure or muddled. 

mist up

verb
  • To become coated with condensation; to fog up. 

  • To become misty. 

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