The Equivocation Flaw on the LSAT: When a Word Changes Meaning
Equivocation happens when a key term means one thing in the premise and another in the conclusion. Learn to catch the shift that breaks the argument.
2026-06-01 · 6 min read
What equivocation means
Equivocation is when an argument uses the same word in two different senses and treats them as if they were the same. The premise is true under one meaning, the conclusion needs another meaning, and the swap is what makes the reasoning fail.
Worked example
"Everything that is natural is good. Arsenic is natural. So arsenic is good."
"Natural" in the first premise hints at "wholesome," but in the second it just means "occurring in nature." The argument trades on the slide between the two senses. Spot the word doing double duty.
A more LSAT-flavored version: "A good knife cuts well. A good person is morally upright. Since this is a good knife, it must be morally upright." The absurdity comes from treating two senses of "good" as one.
How to spot it under pressure
Watch for a word that is emphasized or repeated, especially an abstract one — "free," "natural," "right," "law," "value." Ask whether it means exactly the same thing each time. If the conclusion only works because the word quietly shifted, you have found equivocation.
Answer choices describe it as "relies on a term that is used in two different senses" or "the meaning of a key word shifts over the course of the argument." Verbloom underlines repeated key terms so the meaning shift becomes visible.
Frequently asked questions
How is equivocation different from a straw man?
Equivocation shifts the meaning of a word inside one argument; a straw man distorts someone else's position and then attacks the distortion. Equivocation is about ambiguity; straw man is about misrepresentation.
Is equivocation a common LSAT flaw?
It is less common than causal or conditional flaws but appears regularly enough that knowing it prevents a frustrating miss when it does show up.
What's the giveaway word pattern?
A single abstract term repeated across premise and conclusion where the two uses don't quite match — that mismatch is the flaw.
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