at ease vs on tenterhooks

at ease

prep
  • Allowed to refrain from being in rigid formation. 

  • Free of anxiety; not stressed or tense. 

  • In a relaxed position with the feet apart rather than at attention. 

on tenterhooks

prep
  • In a state of suspense or apprehension. 

How often have the words at ease and on tenterhooks occurred in a corpus of books? (source: Google Ngram Viewer )