- not official or formal: an unofficial engagement
- not confirmed officially: an unofficial report
- (of a strike) not approved by the strikers' trade union
- (of a medicinal drug) not listed in a pharmacopoeia
WordReference Random House Learner's Dictionary of American English © 2026
un•of•fi•cial /ˌʌnəˈfɪʃəl/USA pronunciation adj.
WordReference Random House Unabridged Dictionary of American English © 2026- not official;
not formal:an unofficial visit.
Collins Concise English Dictionary © HarperCollins Publishers::
unofficial /ˌʌnəˈfɪʃəl/ adj
'unofficial' also found in these entries (note: many are not synonyms or translations):
black section
- Britain
- Church of Jesus Christ of Latter-Day Saints
- Communist China
- fringe
- grapevine
- grey market
- kitchen cabinet
- Nkosi Sikelel' iAfrika
- officious
- Provisional
- Red China
- straw poll
- understanding
- authority
- brain trust
- brain truster
- camarilla
- captain
- esquire
- exhibition game
- genro
- gray eminence
- hearsay
- informal
- legislative council
- Manhattan Project
- misery index
- mulligan
- parastatal
- record
- return
- Teamsters Union
- Triple Crown
- straw vote