Hijack
In general hijack refers to taking control over something and causing it to do something else. The most common type of hijacking is when malware infects your computer and redirects your web browser, home page, or search engine to a malicious site or somewhere you don't want to be. When a computer becomes infected usually installing a program such as Malwarebytes can remove and fix the infection. See the below link for additional suggestions and help.
Also see: Clickjacking, DNS hijacking, Redirect, HijackThis, Security definitions