decline vs gap

decline

noun
  • A sloping downward, e.g. of a hill or road. 

  • A weakening. 

  • Downward movement, fall. 

  • A reduction or diminution of activity. 

  • The act of declining or refusing something. 

verb
  • To choose not to do something; refuse, forbear, refrain. 

  • To run through from first to last; to recite in order as though declining a noun. 

  • To cause to decrease or diminish. 

  • To bend downward; to bring down; to depress; to cause to bend, or fall. 

  • To turn or bend aside; to deviate; to stray; to withdraw. 

  • To move downwards, to fall, to drop. 

  • To inflect for case, number, gender, and the like. 

  • To reject a penalty against the opposing team, usually because the result of accepting it would benefit the non-penalized team less than the preceding play. 

  • To become weaker or worse. 

  • To recite all the different declined forms of (a word). 

gap

noun
  • A mountain or hill pass. 

  • A vacancy, deficit, absence, or lack. 

  • The shortfall between the amount the medical insurer will pay to the service provider and the scheduled fee for the item. 

  • An opening in anything made by breaking or parting. 

  • A hiatus, a pause in something which is otherwise continuous. 

  • An opening allowing passage or entrance. 

  • An opening that implies a breach or defect. 

  • (usually written as "the gap") The disparity between the indigenous and non-indigenous communities with regard to life expectancy, education, health, etc. 

  • An unsequenced region in a sequence alignment. 

  • The regions between the outfielders. 

  • A vacant space or time. 

  • A sheltered area of coast between two cliffs (mostly restricted to place names). 

verb
  • To leave suddenly. 

  • To notch, as a sword or knife. 

  • To check the size of a gap. 

  • To make an opening in; to breach. 

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