/ ˌʌnəˈfɪʃl; NAmE / adjective
1.
that does not have permission or approval from sb in authority :
an unofficial agreement / strike
Unofficial estimates put the figure at over two million.
2.
that is not part of sb's official business :
The former president paid an unofficial visit to China.
OPP official
► un·offi·cial·ly / -ʃəli; NAmE / adverb