plunging vs rushing

plunging

adj
  • That descends steeply. 

  • Aimed from higher ground, as fire upon an enemy. 

  • Very low-cut. 

noun
  • A headlong violent motion like that of a horse trying to throw its rider. 

  • An occurrence of putting or sinking under water or other fluid. 

rushing

adj
  • Rapidly flowing or surging. 

noun
  • A rapid surging motion. 

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