Which word best describes someone who is gullible?

The word "credulous" precisely captures the essence of someone who is gullible. A credulous person is one who is easily deceived or tricked because they tend to believe things readily without sufficient evidence or doubt. This term conveys a sense of naivety or willingness to trust, which aligns perfectly with the characteristics of gullibility.

In contrast, the other words do not share this specific meaning. "Cursory" refers to something done hastily and without attention to detail, which has no connection to the concept of being easily fooled. "Daunt" means to intimidate or discourage someone, which again is unrelated to the idea of gullibility. "Culpable" refers to being deserving of blame or responsibility for a fault or wrong, which does not imply a lack of critical thinking or an easily deceived nature. Thus, "credulous" is the only word that accurately describes someone who is gullible.