rattletrap vs unwavering

rattletrap

adj
  • Mechanically unreliable or in disrepair. 

noun
  • A mechanical device, particularly an automobile, that is worn out, run down, or mechanically unreliable as indicated by noises it makes in operation. 

unwavering

adj
  • Always on course and steady. 

  • Not doubting or unsure; decisive, firm, resolute. 

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