anyone's guess vs nonplus

anyone's guess

noun
  • A mystery; something unpredictable. 

nonplus

noun
  • A state of bewilderment or perplexity. 

verb
  • To bewilder or perplex (someone); to confound, to flummox. 

How often have the words anyone's guess and nonplus occurred in a corpus of books? (source: Google Ngram Viewer )