Not official: the unofficial election results. (adjective)
Not acting officially: an unofficial adviser. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "unofficial" in a sentence
"The foreign ministers, he says, have agreed to what he called an unofficial ceasefire, to allow in unarmed Indonesian military and civilian observers to enforce the ceasefire, and to hold further bilateral talks with Indonesian participation in the near future."
"Must emphasise that the word "unofficial" in that quote."
"In the past, you have been involved in conducting what you call unofficial conversations with Taiwan's NSC director, Mr. Ding Mou-shih."