precarious vs unflappable

precarious

adj
  • Dangerously insecure or unstable; perilous. 

  • Relating to incipient caries. 

  • Depending on the intention of another. 

unflappable

adj
  • Remaining composed and level-headed at all times; impossible to fluster; not becoming frustrated or irritated easily. 

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