I'll pass on that, 8 letters
Unh-uh, 8 letters
Polite decline, 8 letters
Polite refusal, 8 letters
Polite turndown, 8 letters
Words of refusal, 8 letters
Polite response, 10 letters
Forget it!, 12 letters
I don't know what melancholy means and I'm..., 15 letters
Is it true you plan to shave your beard?, 21 letters