unofficialun·of·fi·cial /ˌʌnəˈfɪʃəl◂/ adjectiveadj1without formal approval and permission from the organization or person in authorityHe made his complaint through unofficial channels.
2not made publicly known as part of an official planOur unofficial policy is to grant two days’ paternity leave.
—unofficially adverbadvThe trade union was unofficially formed in 1972.