Our friend Jonathan Caws-Elwitt spotted this lovely pfft variant in the wild:


We can verify that p'fft is an appropriate response to "blankety-blank nonsense" (as noted on the first page of Budget Weddings For Dummies).  Relatedly, Wodehouse has written: "He had a dim sort of idea that it began with an F or a G, but beyond that his mind was a blank" (The Small Bachelor).

But did you know that p'fft comes down to us from an ancient Chinese expression meaning, "May your children and grandchildren never murmur as they carry out the careful and brilliant virtue of their predecessors"?

It's commonly assumed that the apostrophe in p'fft stands for an f, the concept being that an f-too-many is overwhelming.  Indeed, Wodehouse notes: "You could have knocked me down with a f" (Right Ho, Jeeves).  Yet the truth is more interesting.  The apostrophe actually stands for a hyphen, swept upwards as it were by the breath of the expression.