unregistered

adjective

1. recorded, as in a register or book; enrolled.
2. Commerce. officially listing the owner’s name with the issuing corporation and suitably inscribing the certificate, as with bonds to evidence title. Abbreviation: r
3. officially or legally certified by a government officer or board: a registered patent.
4. denoting cattle, horses, dogs, etc., having pedigrees verified and filed by authorized associations of breeders.

adjective

1. not registereddriving an unregistered vehicle