Illegal in particular doesn't really have a proper legal meaning in many juristictions. Generally, in lay terms, unlawful means to act in contrary to the law,

Illegal in particular doesn't really have a proper legal meaning in many juristictions. Generally, in lay terms, unlawful means to act in contrary to the law, so it covers anything where a) the police come after you and charge you with a crime b) a governmental body charges you with an offense or imposes a penalty for a breach of the law or c) you are in a situation where a third party can sue you and win for damages etc due to you acting in contrary to your legal obligations. Generally speaking "illegal" is only used to describe a and b, or just a. But to be honest so many people get them wrong that there's a legitimate argument that the layperson difference is meaningless nowadays.