Not being acquainted; not conversant: unfamiliar with the roads here. (adjective)
Not within one's knowledge; strange: unfamiliar faces. (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 "unfamiliar" in a sentence
"These gentlemen were using a phrase unfamiliar to many in northern and eastern linguistic regions but easily understood by “country” talkers and especially black Americans; it is deeply rooted in the usages of some of the great contributors to the English language."
"It's a throw-away line in a story on page A15, a mention of a name unfamiliar to many Americans."
"Well, for those find the term unfamiliar, I want to give a brief description of Xobni."