|3.||the act of swooping|
|4.||a swift descent|
|[Old English swāpan to sweep; related to Old High German sweifan to swing around, Old Norse sveipa to throw]|
"Oh, Hell-Kite! All? What, All my pretty Chickens, and their Damme, At one fell swoope?" ["Macbeth," IV.iii.219]
in one fell swoop
see one fell swoop.