hand waving

• hand-waving, handwaving

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hand waving (plural hand wavings)

1. (idiomatic) Discussion or argumentation involving approximation, vagueness, educated guessing, or the attempt to explain or excuse vagaries.

   The sales pitch sounded good, but there was a lot of hand waving about the price.

   • 2000 August 21, “letter”, in Time:

     Protesters who demand that this brilliantly humane enterprise be stopped should have their motives questioned. Their protest is nothing but the mindless hand waving of Luddites.