decline vs fallback

decline

noun
  • Downward movement, fall. 

  • A weakening. 

  • A reduction or diminution of activity. 

  • The act of declining or refusing something. 

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

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). 

fallback

noun
  • An act of falling back. 

  • Pulverised material that falls back to earth after a nuclear explosion; fallout. 

  • A backup plan or contingency strategy; an alternative which can be used if something goes wrong with the main plan; a recourse. 

  • A reduction in bitumen softening point, sometimes called refluxing or overheating, in a relatively closed container. 

adj
  • That can be resorted to as a fallback. 

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