unregister

Etymology

un- + register

verb

1. (transitive) To undo the process of registration for.
   To unregister a DLL and remove the corresponding entries from the registry, add the /u switch to the command[…] 1999, John Papa, C. Caison, Matt Brown, Professional ADO RDS programming with ASP, page 252
2. (intransitive) To undo a registration process.
   Before you uninstall the software and rid yourself of ICQ forever, take the time to go online and unregister yourself (see the previous sections in this chapter). By unregistering, you remove your name from the ICQ computers. 2000, Peter Weverka, Michael Taylor, ICQ 2000 for dummies, page 34