fallacious

/fəˈleɪʃəs/ (bre, ipa) · /fəˈleɪʃəs/ (ame, ipa) · /fə-ˈlā-shəs/ (ame, mw)

fallacious — adjective

  • fallaciouspositive
  • more fallaciouscomparative
  • most fallacioussuperlative

1. containing a mistake in logic that makes an argument, belief, or conclusion inva

1.形容詞C1
釋義

containing a mistake in logic that makes an argument, belief, or conclusion invalid.

例句

Priya pointed out that the student's conclusion was fallacious because it ignored the data from the control group.

fallacious + that-clause (conclusion-based reasoning)

Yuna proved the claim that "expensive headphones last longer" was fallacious when hers broke after just two weeks.

prove + claim + fallacious — verb-object-adjective complement structure

同義詞
  • flawed

    less formal than fallacious; suggests an error or weakness but not necessarily a logical mistake.

  • unsound

    similar register; often used in formal or academic writing, especially about arguments or methods.

  • invalid

    specifically about arguments that break formal logical rules; stronger and narrower.

反義詞
  • valid

    an argument that follows logical rules and is well-supported.

  • sound

    an argument that is both logically valid and based on true premises.

用法筆記

Frequently modifies nouns such as argument, reasoning, assumption, conclusion, or belief. The sense describes an error in thinking, not necessarily a deliberate lie — distinguish from Sense 2 (INTENDED TO DECEIVE), where the falsehood is knowingly crafted.

常見錯誤

❌The weather forecast was fallacious because it said it would rain.
✅The weather forecast was wrong because it said it would rain.
💡'fallacious' applies to reasoning or arguments, not everyday factual errors.
❌His fallacious smile made everyone uncomfortable.
✅His fallacious argument confused the audience.
💡'fallacious' describes flawed logic or deceptive ideas, not a person's expression or mood.

2. designed or crafted to trick people into believing something untrue.

2.形容詞C1
釋義

designed or crafted to trick people into believing something untrue.

例句

The company was fined for making fallacious claims about its weight-loss supplement on social media.

fallacious + claims — common collocation in consumer protection contexts

Noa ignored the fallacious investment offer because it promised impossible returns with no risk.

同義詞
  • deceptive

    slightly broader — something can be deceptive without being deliberately false (e.g. appearances); fallacious is more about crafted falsehood.

  • misleading

    less strong than fallacious; misleading information may be unintentionally confusing, whereas fallacious implies intent.

  • fraudulent

    stronger and legal in tone; implies illegality, whereas fallacious can describe deception without legal violation.

反義詞
  • truthful

    conveys honest, accurate information.

  • accurate

    factually correct; opposite of deliberately misleading.

用法筆記

Stronger than 'misleading' — this sense implies the deception is intentional, not accidental. Common in legal, financial, and consumer-protection contexts. Subject can be a claim, statement, advertisement, promise, report, or information.

常見錯誤

❌The broken clock gave a fallacious time.
✅The broken clock gave the wrong time.
💡machines and objects do not deceive intentionally; use 'wrong' or 'incorrect'.
❌She was fallacious about her age.
✅She made a false statement about her age.
💡'fallacious' is not used for a person; use 'dishonest' or 'lying' instead.