But the term is "illegal immigrant" and denotes a person that illegally entered or resides in a country. Changing it to "undocumented immigrant" makes it sound like a simple absence of documentation due to a procedural fault, but that's not the issue. Generally they entered illegally and in cases where they stay past a visa, that action is also illegal.
The term is in fact 'alien'. Strictly speaking the law refers to 'illegal immigration' as a proscribed activity, but it's not extended to individuals, all of whom are classified as aliens (hence the old-fashioned term 'illegal alien,' which is no longer current since the passage of IIRIRA in 1994 but still exists in many older official documents. http://www.uscis.gov/tools/glossary
I'm personally OK with 'illegal immigrant,' but when you say a person is illegal (qua 'illegals') then that comes across as an implicit denial of legal personhood. This might seem pedantic, but the US constitution already distinguishes between rights of citizens and of persons in general, while many people who object to illegal immigration would like to deny the rights to accrue to all persons to those who have immigrated illegally, including myself. Thus, the term has become somewhat loaded to a greater degree than the authors of the current law may have intended.
I think all people have rights, illegal immigrant or not. I also happen to think if you are here illegally you should be deported and required to immigrate legally. No ill will involved. I don't think of immigrants as sub-standard and anything even remotely like that (as an unfortunately large group of people think). Most of the population of the US is immigrants, strictly speaking.
As for terminology, IANAL. From my viewpoint if you illegally immigrate, through action or inaction, then you are an illegal immigrant. I've never much liked the term alien as it has also been used to describe little green men and such.
I think taking issue with calling a person illegal is splitting hairs, but I'll go along. The person isn't illegal, but their residency status is illegal.
And my last point, to reiterate on what I said earlier, I have no ill will towards illegal immigrants and know they have basic rights. I would expect they get treated fairly under our laws (well, as fair as out laws can be). That being said, they are not here legally and I would expect that changes the legal avenues available to them.
You can argue that "undocumented immigrant" doesn't capture the actual meaning, but that doesn't make jorgeleo's point any less valid: the action is illegal, not the person.
But the person committed the action, so it doesn't seem unfair for the description to describe both. Much like how we use various descriptions to describe people based on their actions.
