tremble vs vertigo

tremble

noun
  • A shake, quiver, or vibration. 

verb
  • To shake, quiver, or vibrate. 

  • To fear; to be afraid. 

vertigo

noun
  • The act of whirling round and round; rapid rotation. 

  • A sensation of whirling and loss of balance, caused by looking down from a great height or by disease affecting the inner ear. 

  • A disordered or imbalanced state of mind or things analogous to physical vertigo; mental giddiness or dizziness. 

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