the GNU version of the Collaborative International Dictionary of English
adj. Not heard; not perceived by the ear.
adj. Not granted an audience or a hearing; not allowed to speak; not having made a defense, or stated one's side of a question; disregarded; unheeded.
adj. Not known to fame; not illustrious or celebrated; obscure.
The Century Dictionary and Cyclopedia
Not heard; not perceived by the ear.
Not admitted to audience or given a hearing; not permitted to speak for one's self.
Not known to fame; not celebrated.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. not necessarily inaudible but not heard
Word Usage
"BILL PAXTON, of the Texas Forest Service, describing the moisture content of Texas grass Sunday at what he called an "unheard of" 2% as wildfires continued burning in the drought-stricken state, where more than 34,000 acres have been consumed"