fearful vs tremulous

fearful

adj
  • Tending to fear; timid. 

  • Frightening; causing fear. 

adv
  • Extremely; fearfully. 

tremulous

adj
  • Timid, hesitant; lacking confidence. 

  • Trembling, quivering, or shaking. 

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