Three Latin roots run through this topic. cred means believe (you know it from credit and incredible), fid means trust or faith (as in confident), and ver means true (as in very, which first meant “truly”). Spot one of them, and you have a strong clue to the meaning.
Key idea
cred = believe: credible, incredulous, credulous, credence. fid = trust: fidelity, confidant, diffident. ver = true: veracity, verify, verdict.
Watch the endings: -ible (able to be) makes credible, “able to be believed”; -ulous (inclined to) makes credulous, “inclined to believe,” too easily.
The ten words
The roots at work
Common mistake
A story is incredible (hard to believe); the listener is incredulous (not believing). Credulous means too ready to believe, the opposite of incredulous. A confidant (a trusted friend) is not confident (sure of yourself).
| word | who or what | means |
|---|---|---|
| incredible | a story | hard to believe |
| incredulous | a listener | not believing |
| credulous | a listener | believing too easily |
| credible | a story or a witness | believable |
| confidant | a person | someone you trust with secrets |
| confident | a person | sure of yourself |
| diffident | a person | not sure of yourself; shy |