Conniver (noun)

1. A person who participates in or is involved in a secret plan, especially one that is illegal or unethical.
2. A person who secretly cooperates with others in an illegal or unethical plan or scheme.

Origin:

From the verb 'connive', which means 'to participate in or be involved in a secret plan, especially one that is illegal or unethical'.

Examples:

1. The conniver was caught and punished for his role in the illegal scheme.
2. The conniver's deception was discovered and he was no longer trusted.
3. The conniver was revealed to be the mastermind behind the fraud.
4. The conniver tried to escape prosecution by fleeing the country.
5. The conniver's actions hurt many innocent people and destroyed reputations.