downright vs not at all

downright

adv
  • Really; actually; quite 

adj
  • Directly to the point; plain 

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

  • Complete; absolute 

not at all

adv
  • Not in the least. 

intj
  • Used similarly to you're welcome, as a conventional reply to an expression of gratitude. 

  • Don't worry about it (response to worry or an apology) 

How often have the words downright and not at all occurred in a corpus of books? (source: Google Ngram Viewer )