adj. Of reasoning, that is based on something that is not true.
the GNU version of the Collaborative International Dictionary of English
adj. Without a base; having no foundation or support.
The Century Dictionary and Cyclopedia
Without a base; having no foundation or support.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. without a basis in reason or fact
Word Usage
"Paul Coggins, a lawyer for Mr. Ensign, said he looked forward to the ethics committee reaching the same conclusion as the Justice Department on what he called baseless allegations."