I. “+ adjective
1.
a. : not belonging to, emanating from, or sanctioned or acknowledged by a government or governing body
a sort of unofficial mayor of the village — Siegfried Sassoon
the unofficial capital
an unofficial estimate
b. of a drug : not recognized by the legal standards or government of a country
c. : nominated or elected from among the native inhabitants of a British dependency and holding no appointment from the Colonial Office in the public service
a governor's council with an unofficial minority
there is no legislative council in the Dependent Empire without unofficial members — Martin Wight
— compare official
2. : not sanctioned, authorized, or acknowledged by a group, class, or society
proud of their unofficial power as mothers — E.H.Erikson
the custom of awarding prizes … substitutes one certified good play for half a dozen unofficial good plays — Russell Maloney
• un·officially “+ adverb
II. noun
: an unofficial member of a legislature in a British dependency