in one foul swoop

== English == === Etymology === Mondegreen variant of in one fell swoop, where "fell" (of a strong and cruel nature; eager and unsparing; grim; fierce; ruthless; savage) is misheard as "foul" (disgusting) or "fowl" (a bird). === Prepositional phrase === in one foul swoop (idiomatic, proscribed) (Achieved or completed) with a single action; in a single stroke.