Living illegally with someone means staying in a place or dwelling without proper permission, documents, and lawful authorization. The term "live illegally with" can have many synonyms and can be referred to in different ways, such as squatting, residing unlawfully, unauthorized dwelling, or cohabitating illegally. These synonyms are often used interchangeably, and they all imply living in a place where the person has no legal right to be. It is essential to remember that living or cohabitating illegally can have serious consequences, and it is always best to seek legal assistance and obtain proper permits and documents to avoid legal troubles.