staggering vs tough proposition

staggering

noun
  • The motion of one who staggers. 

  • The condition of being staggered or amazed. 

  • In animation, the repetition of a sequence of frames to show struggling effort 

adj
  • Lurching, floundering. 

  • Incredible, overwhelming, amazing. 

tough proposition

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