TOEIC Link Part 5: credible versus credulous
Credible and credulous grow from the same Latin root credere, "to believe," so test-takers treat them as the same idea dressed in different endings — but they describe opposite ends of the believing transaction. Credible is an adjective meaning believable and worthy of trust. Credulous is an adjective meaning too willing to believe, easily fooled. Part 5 drops one into a sentence where the question is whether the blank praises a trustworthy source or warns about a gullible reader. For the wider set of look-alike traps, start with the commonly confused word pairs master index.
The core rule: worthy of belief versus too quick to believe
- credible = believable; deserving to be trusted (adjective). The auditor found the financial statements credible and well documented. / She gave a credible explanation for the delay. It answers can this be believed? and describes the source, claim, or evidence being judged. Link credible to convincing and reliable: it points at the thing you are deciding to trust.
- credulous = too ready to believe; easily deceived (adjective). A credulous investor accepted the promise of guaranteed returns without checking. / The scam targeted credulous shoppers with fake reviews. It answers who believes too easily? and describes the person doing the trusting. Link credulous to gullible and naive: it points at a weakness in judgment, and it carries a negative tone.
The key difference: credible describes something that earns belief, while credulous describes someone who gives belief too freely. One is a compliment to a source; the other is a criticism of a reader. If the blank rates a claim or witness, choose credible; if it describes a person who is easily taken in, choose credulous.
Why Part 5 likes this pair
Because both words come from the same root about believing, the shared origin invites a wrong guess. Part 5 builds a sentence where either the reliability of a source or the gullibility of an audience could seem to fit, then rewards the reader who notices which side of the transaction the blank sits on.
The committee accepted the report because its data and sources were entirely __.
A word rating the report as believable needs credible.
Fraudsters count on a small number of __ customers who will believe any promise.
A word describing people who believe too easily needs credulous.
Spotting the clue
Decide whether the blank describes a source being judged or a person doing the believing:
- Does the blank rate a claim, report, witness, or explanation as worth trusting (paired with evidence, sources, testimony)? → choose credible (a credible account, credible evidence, a credible threat).
- Does the blank describe a person or audience too willing to believe (paired with scams, promises, rumors)? → choose credulous (a credulous buyer, credulous readers, too credulous to question it).
A quick test: can you replace the blank with believable or convincing? Then it is credible. Can you replace it with gullible or naive? Then it is credulous. Watch the surrounding tone too — credible travels with proof and reliability, while credulous travels with deception and warnings. Because both are adjectives whose direction is easy to reverse, this pair sits alongside other look-alike traps such as discreet versus discrete and complement versus compliment.
Common Part 5 patterns
- Anything rating a source or claim wants credible: a credible witness, credible data, a credible alternative, remain credible.
- Anything describing an easily-fooled person wants credulous: a credulous audience, credulous investors, less credulous than before.
Quick reference
- credible = believable, worthy of trust (adjective) → describes the source or claim; pairs with evidence and reliability.
- credulous = too ready to believe, gullible (adjective) → describes the person; carries a negative tone.
If the blank judges whether something can be believed, it is credible; if it describes someone who believes too easily, it is credulous. Keep the two straight and this pair becomes a reliable point rather than a coin flip.