at ease vs sudden

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. 

sudden

adj
  • Happening quickly and with little or no warning. 

adv
  • Suddenly. 

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