Illegality is basically any conduct that is against the law. It is any activity or conduct not allowed by the law, it is something the law forbids.
The principle of illegality means that as a matter of public policy a person has no right in law to recover or benefit from his own illegal, criminal, base,Immoral or wrongful act. This means that if a plaintiff had been involved in an illegality, there is no duty of care, no legal right and no remedy for him in law. He is not entitled to recover from a wrong suffered by him,