Unregistered

Part of speech: adjective

Definitions

1. Not included in any official list or registry systems
2. Lacking official entry or acknowledgment in any formal registry or database
3. Describes something that has not been formally documented or recorded by authorized entities

Etymology: "Unregistered" is a plain formation: the prefix "un-", meaning "not", attached to "registered," the past participle of "register." The prefix descends from Old English "un-", which has been used since the earliest English to reverse or negate an adjective or participle, so English speakers could form a negative of almost any "-ed" word on demand. "Register" itself came into English from Medieval Latin "registrum," a record book, so the negated form simply describes something not entered in such a book.

Synonyms: unlisted, unauthorized, unofficial

Antonyms: registered, official, authorized