Antonyms of adj well-grounded

1 sense of well-grounded

Sense 1
reasoned, sound, well-grounded -- (logically valid; "a sound argument")

INDIRECT (VIA valid) -> invalid -- (having no cogency or legal force; "invalid reasoning"; "an invalid driver's license")

Similarity of adj well-grounded

1 sense of well-grounded

Sense 1
reasoned, sound, well-grounded -- (logically valid; "a sound argument")
       => valid (vs. invalid) -- (well grounded in logic or truth or having legal force; "a valid inference"; "a valid argument"; "a valid contract")