Definitions

1. adjective

not officially recognized or sanctioned; not part of an official system or organization

“The unofficial rules of the game were not well-defined and caused confusion among players.”

2. noun

something that is not officially recognized or sanctioned

“The unofficial history of the city, which included stories from local residents, was compiled into a book.”

3. adverb

in an unofficial manner or capacity

“She was working unofficially as a consultant for several months before being hired full-time.”