So, because people have been immigrating (settling more or less permanently in new areas all over the planet — the definition you provided earlier) since long before there were immigration laws, it must be possible to be an immigrant whether there are immigration laws or not and whether those laws are followed or not. The act of immigrating is what the law seeks to regulate, not what the law seeks to define. The law defines the legal process for immigrating, which in turn triggers the application of the term “legal” or “illegal” to the descriptor “immigrant”. An animal can meet the definition of immigrant provided it has settled in a new territory. Immigration is merely a derivative of “migrate” (from the Latin migrare, which merely means changing residence or condition), which has to do with movement from one place to another.
The law, which may be just or unjust and which only carries so much weight (i.e., misdemeanor vs. felony) may in certain cases influence how long a person remains in a place but is at best an imperfect indicator of it. How long must a person settle in a new place before they are considered an immigrant, either legally or otherwise? To define immigrant as “permanent”, as you did in an earlier post, and then argue that someone who has lived in a country for 10 years without documentation isn’t an immigrant but a person that has lived there for five with it is makes no sense given you’ve already conceded that a degree of permanence has something to do with it. If a person is caught driving without a license we don’t say the word “driver” doesn’t apply to them. We say they are an unlicensed driver. These people are immigrants, pure and simple. They left their country to live in another, and that’s the definition of the word.