Meaning & use
fallacious
Last updated
UK/fəˈleɪʃəs/
US/fəˈleɪʃəs/
Meaning
adjectivecomparableformal
Based on a mistake in reasoning or a false idea, and so not valid.
Grammar: Describes arguments and beliefs, not people: a fallacious claim.
The report used fallacious reasoning to reach its conclusion.
It is fallacious to assume that expensive means better.
Critics dismissed the argument as fallacious.
Word forms
| comparative | more fallacious |
|---|---|
| superlative | most fallacious |
Common combinations
- fallacious argument
- He presented a fallacious argument.
- fallacious reasoning
- The logic class studied fallacious reasoning.
- fallacious assumption
- It was a fallacious assumption that sales would rise.
- fallacious claim
- The ad made a fallacious claim.
Synonyms and how they differ
- false
- Is a plain word for untrue and does not point to faulty reasoning.
- illogical
- Stresses a failure of logic, but not necessarily a false conclusion.
- misleading
- Suggests giving a wrong impression, whether or not by faulty logic.
- erroneous
- Is formal and means wrong because of a mistake.
Opposites
Word family
- fallacy noun
- a mistaken belief or faulty argument
- fallaciously adverb
- in a way based on faulty reasoning
Commonly confused: fallacious or fallible?
fallacious vs fallible
Fallible means capable of making mistakes, and describes people; fallacious describes arguments.
Practice
Which would be called fallacious?
Choose one answer.
Fallacious describes reasoning with a flaw that makes it invalid. The other options are not arguments.
Make it your own
Write a sentence using “fallacious”, then check it and compare it with the examples above.
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