Explanation:

- Paranoid: This word describes someone who has an irrational and persistent belief that others are trying to harm them. It involves extreme distrust or suspicion.

- Option 1: Convinced: To be convinced means to be certain or confident about something. This is unrelated to paranoia as it doesn’t involve suspicion.

- Option 2: Trustful: Someone who is trustful tends to believe in the honesty or integrity of others, which is the opposite of being paranoid.

- Option 3: Committed: Being committed means being dedicated or loyal to a cause or person. It does not relate to suspicion or distrust.

- Option 4: Distrustful: This means being unwilling or unable to trust others, similar to being suspicious and wary, like a paranoid person.

- Option 4: Distrustful is the most appropriate synonym for paranoid because both involve a lack of trust and suspicion of others.