noun which may take the genitive case particle 'no'
Describes something not officially recognized or approved, such as a record, event, or organization.
That record is unofficial, so it is not officially recognized.
Participating in an unauthorized event is at your own risk.
非公式 also means 'unofficial' but is more common and broader; 非公認 emphasizes lack of official recognition or approval.
Compound of 非 (hi, 'non-') and 公認 (kōnin, 'official recognition').