Let us take a specific situation.
You are facing a person you find extremely annoying. The person is finding faults in your ways and pointing them out in a rather blunt manner. They are making high demands, being obnoxious and really getting under your skin. Worst of all, they are right on all accounts and your argument with that person is quickly turning into a losing battle.
And on top of that, the person is using a really annoying dialect, something you can't hold against them but it really brushes you the wrong way.
Yet another point in your argument is raised, stated in that annoying dialect, and as you utter your angry, frustrated (and wrong) rebuttal, you find yourself replying using the same terrible dialect. You stop and correct yourself immediately, but during the second before correcting yourself, you...
scoff? The dictionary definition suggests scoffing is more similar to annoyed, dismissive laugh. This is more about grinding your teeth in frustration. How would you describe such an expression?