hi·jack / ˈhīˌjak/ (also high·jack) • v. [tr.] illegally seize (an aircraft, ship, or vehicle) in transit and force it to go to a different destination or use it for one's own purposes: three armed men hijacked a white van | [as n.] (hijacking) an eight-hour hijacking. ∎ steal (goods) by seizing them in transit. ∎ take over (something) and use it for a different purpose: the organization had been hijacked by extremists.• n. an incident or act of hijacking.DERIVATIVES: hi·jack·er n.