Unregistered (adjective)

1. Not having been officially recorded or documented.
2. Not having been entered into a register or list.

Origin:

From the latin word 'inregistratus' meaning 'not registered or recorded'.

Examples:

1. The event was attended by many unregistered participants.
2. The company was operating without a proper license and was considered unregistered.
3. The vehicle was unregistered and could not be driven on public roads.
4. She gave birth to a baby boy who remained unregistered and did not have a birth certificate.
5. The land was unregistered and not recognized by the government.