Not At All Meaning

(idiomatic) Used similarly to you're welcome, as a conventional reply to an expression of gratitude.

Example: 1898, Winston Churchill, chapter 3, The Celebrity:
  Now all this was very fine, but not at all in keeping with the Celebrity's character as I had come to conceive it. The idea that adulation ever cloyed on him was ludicrous in itself. In fact I thought the whole story fishy, and came very near to saying so.
  He's not at all friendly towards his ex-wife.‎
  Thank you for this very thoughtful present. — Not at all.‎