adj. unable to be imagined; inconceivable or mind-boggling; beyond belief
The Century Dictionary and Cyclopedia
Not imaginable; not capable of being imagined, conceived, or thought of; inconceivable.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. totally unlikely
Word Usage
"In his TV speech Saturday, Prime Minister Sharaf said Egypt's citizens are "the root of all sovereignty and source of all authority" — a phrase unimaginable in Mubarak's days."