Word Origin & History
1566, "to move or walk in a stately manner," apparently from a fial. survival of O.E. swapan "to sweep, brandish, dash," from P.Gmc. *swaipanan, from PIE base *swei- "to swing, bend, to turn." Meaning "pounce upon with a sweeping movement" first recorded 1638. Spelling with -oo- may have been influenced
by Scot. and northern England dial. soop "to sweep," from O.N. sopa "to sweep." The noun is attested from 1544. Phrase one fell swoop is from Shakespeare.
"Oh, Hell-Kite! All? What, All my pretty Chickens, and their Damme, At one fell swoope?" ["Macbeth," IV.iii.219]