on thin ice vs shaky

on thin ice

prep
  • In a dangerous, hazardous, or delicate situation; at risk. 

adv
  • dangerously, hazardously, delicately 

shaky

adj
  • Easily shaken; tottering; unsound. 

  • Shaking or trembling. 

  • Wavering; undecided. 

  • Full of shakes or cracks; cracked. 

  • Nervous, anxious. 

How often have the words on thin ice and shaky occurred in a corpus of books? (source: Google Ngram Viewer )