Horsefeathers!

horsefeathers

slang Nonsense or foolishness. Often used as an exclamation to emphasize that something is nonsense. Oh, that's just horsefeathers, and you know it. A: "Tim said he wants to sell the farm!" B: "Horsefeathers! I said no such thing!"
Farlex Dictionary of Idioms.

Horsefeathers!

exclam. Phooey!; Nonsense! Horsefeathers! I did no such thing!
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • horsefeathers
  • flamdoodle
  • martin
  • all my eye
  • all my eye (and Betty Martin)
  • betty
  • fadoodle
  • nonsense
  • a load of nonsense
  • a load of rubbish, nonsense, etc.
References in periodicals archive
When our friends say anything else, he snorts and says "Horsefeathers!" to them.
'Things aren't normal at all!'
To this logic of faulty comparison I can only say: "Horsefeathers!"
LETTERS IN THE EDITOR'S MAILBAG
We hear rubrics like, "No picture, no story," or "That's a newspaper story, not good TV." Horsefeathers! Good people can craft "newspaper" stories into effective, important video.
Mimicking the worst
"The rule's cap-and-trade system will create the incentive for big early reductions in pollution." Horsefeathers! What he's describing is a kind of cruel lottery: If you live downwind from a plant which has bought mercury credits, you lose.
LETTERS IN THE EDITOR'S MAILBAG