from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Having no ground or foundation; unsubstantiated: groundless optimism. See Synonyms at baseless.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Without any grounds to support it; baseless.
from the GNU version of the Collaborative International Dictionary of English
- adj. Without ground or foundation; wanting cause or reason for support; not authorized; false; baseless
from The Century Dictionary and Cyclopedia
- Without ground or foundation; especially, having no adequate cause or reason; not authorized; baseless.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. without a basis in reason or fact
ground + -less (Wiktionary)