difficulty vs wonder

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. 

wonder

noun
  • A mental pondering, a thought. 

  • Something that causes amazement or awe; a marvel. 

  • A kind of donut; a cruller. 

  • Someone very talented at something, a genius. 

  • The sense or emotion which can be inspired by something curious or unknown; surprise; astonishment, often with awe or reverence. 

  • Something astonishing and seemingly inexplicable. 

verb
  • To be affected with surprise or admiration; to be struck with astonishment; to be amazed; to marvel; often followed by at. 

  • To ponder; to feel doubt and curiosity; to query in the mind. 

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