difficulty vs hurdle

difficulty

noun
  • The state of being difficult, or hard to do. 

  • Physical danger from the environment, especially with risk of drowning 

  • An obstacle that hinders achievement of a goal. 

  • An objection. 

  • An awkward situation or quarrel. 

  • That which cannot be easily understood or believed. 

hurdle

noun
  • An obstacle, real or perceived, physical or abstract. 

  • An artificial barrier, variously constructed, over which athletes or horses jump in a race. 

  • A movable frame of wattled twigs, osiers, or withes and stakes, or sometimes of iron, used for enclosing land, for folding sheep and cattle, for gates, etc.; also, in fortification, used as revetments, and for other purposes. 

verb
  • To compete in the track and field events of hurdles (e.g. high hurdles). 

  • To overcome an obstacle. 

  • To jump over something while running. 

  • To hedge, cover, make, or enclose with hurdles. 

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