of course not

of course not

Certainly not. The phrase implies that a negative response should be obvious. A: "Would you mind picking me up from the airport?" B: "Of course not! What time do you land?" A: "Are you going to sign up for this overtime refund scheme?" B: "No, of course not, it's a total rip-off!"
See also: course, not, of
Farlex Dictionary of Idioms.

of ˈcourse not

(also ˈcourse not informal) used to emphasize the fact that you are saying ‘no’: ‘Are you going?’ ‘Of course not.’ ‘Do you mind?’ ‘No, of course not.’
See also: course, not, of
Farlex Partner Idioms Dictionary
See also:
  • certainly
  • certainly not
  • not for a second
  • not for a minute
  • not for a moment
  • aint
  • ain't
  • not for a/one minute/moment/second/instant
  • not for a instant
  • not by any means
References in classic literature
'Why, of course not, Pa, said Bella, giving him another shake or two.
"Why, n-no, of course not," rejoined Milly, in hasty conciliation, as she reached for the medicine bottle.
But writing on Twitter on Wednesday evening, Cuevas Barron rejected the claim, saying 'Of course not!'
If they say to run the train with some adjustments, we will consider, of course not at our expense.
Of course not, but it is an alternative that could send a message to the world that we're serious about taking responsibility for our own energy needs.
'Not on every Welsh mountaintop, of course not, not off every beach in Wales or Northern Ireland of course not.
Will Mr Clarke resign - of course not. Will heads roll -of course not.
"Will you be compelled to resign?" he asked, and I replied, "Of course not."
Of course not. Is the alternative--trial by judge--any better?
Of course not. But now you have another tool to help you work through it.
Of course not. They will finish in the middle of the table."
Of course not. But every intelligence estimate I've seen predicts that the most likely delivery system of the next bomb is some kind of truck or other street level device.
Of course not, because besides being one of the few creatures that Lucifer spawned from his rectum, that possum was so decayed it revealed a frightening insect laden bone structure you had erased from your childhood memories ...
No, of course not. But, like golf, its intricacies are all made up of fundamentals that must be performed properly.
'Of course not. So why should we allow local government to limit where we can shop?' "