fallacy

1 a false idea or belief the once-common fallacy that girls just weren't any good at math Synonyms delusion, error, falsehood, falsity, hallucination, illusion, misbelief, misconception, myth, old wives' tale, untruth Related Words factoid; superstition; fiction, pretense (or pretence); distortion, inaccuracy, misapprehension, miscomprehension, misinterpretation, misjudgment, misperception, misunderstanding; misinformation, misknowledge, misreport, misrepresentation, misstatement; sophism, sophistry; fib, half-truth, lie, story, tale Antonyms truth, verity

2 the quality or state of being false the fallacy of the notion of spontaneous generation was demonstrated by the Dutch naturalist Leeuwenhoek Synonyms erroneousness, fallaciousness, falsehood, falseness, falsity, untruth Related Words speciousness, spuriousness; deception, deceptiveness, delusion; inaccuracy, incorrectness; dishonesty, mendaciousness, mendacity, untruthfulness Near Antonyms accuracy, actuality, correctness, factuality, factualness, genuineness; credibility, honesty, trustworthiness, truthfulness, veracity Antonyms truth, verity