swoop / swoōp/ • v. 1. [intr.] (esp. of a bird) move rapidly downward through the air: the barn owl can swoop down on a mouse in total darkness | the aircraft swooped in to land. ∎ carry out a sudden attack, esp. in order to make a capture or arrest: investigators swooped on the Graf family home.2. [tr.] inf. seize with a sweeping motion: she swooped up the hen in her arms.• n. a swooping or snatching movement or action: four members were arrested following a swoop by detectives on their homes.PHRASES: at (or in) one fell swoopsee fell4 .