not at all vs though

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) 

though

adv
  • Despite that; however. 

  • Used to intensify statements or questions; indeed. 

conj
  • Despite the fact that; although. 

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