Swoop
mid 16th century (in the sense ‘sweep along in a stately manner’): perhaps a dialect variant of Old English swāpan (see sweep). The early sense of the noun was ‘a blow, stroke’.
wiktionary
From Middle English swopen, from Old English swāpan(“to sweep”). See also sweep.
etymonline
swoop (v.)
1560s, "to move or walk in a stately manner," apparently from a dialectal survival of Old English swapan "to sweep, brandish, dash," from Proto-Germanic *swaip-, from PIE root *swei- (2) "to bend, turn" (see swivel (n.)). Meaning "pounce upon with a sweeping movement" first recorded 1630s (see swoop (n.)). Spelling with -oo- may have been influenced by Scottish and northern England dialectal soop "to sweep," from Old Norse sopa "to sweep." Related: Swooped; swooping.
swoop (n.)
1540s, "a blow, stroke," from swoop (v.). Meaning "the sudden pouncing of a rapacious bird on its prey" is 1605, from Shakespeare:
Oh, Hell-Kite! All? What, All my pretty Chickens, and their Damme, At one fell swoope? ["Macbeth," IV.iii.219]