at all vs downright

at all

adv
  • Indicating degree, quantity or frequency greater than zero: to the slightest degree, in any way, at any time or in any circumstance. 

downright

adj
  • Directly to the point; plain 

  • Using plain direct language; accustomed to express opinions directly and bluntly; blunt. 

  • Complete; absolute 

adv
  • Really; actually; quite 

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