Synonyms of ill-founded

1 Syllable
null, mad, bad, wrong, void
2 Syllables
untrue, unsound, false
3 Syllables
sophistic, fallacious, invalid, baseless, reasonless
4 Syllables
unscientific, illogical, irrational, nugatory, unreasoned
5 Syllables
unreasonable
6 Syllables
inoperative