Neutral:
* Gullible: This is the most common and neutral word, simply meaning easily persuaded to believe something.
* Credulous: Similar to gullible, but often implies a willingness to believe without sufficient evidence.
Negative:
* Naive: Suggests a lack of experience or worldly knowledge, making someone easily tricked.
* Dupable: Implies that someone is easily manipulated or taken advantage of.
* Simple: Can be derogatory, suggesting a lack of intelligence or sophistication.
* Unsuspecting: Describes someone who is not aware of potential deception or danger.
* Trusting: While not inherently negative, can be used to describe someone who trusts too easily and is therefore easily tricked.
The best word to use depends on the specific context and the tone you want to convey.