What is difference between illegitimate lawless illegal illicit and unlawful?

Illegitimate means a claim which the law does not endorse. "Your claim to own this house is illegitimate."--the law will not back it up. Unlawful means contrary to the civil or criminal law, so that the victim can either get redress or punishment or both. Illegal means contrary to the criminal law. Breaking a contract is not illegal (you cannot be sent to jail over it) but it is unlawful (you can be sued over it). Illicit means the same as unlawful, but is used in much more restricted contexts. Lawless refers to a person who has no regard for the law--a criminal.