Here is a question that is not well posed in my opinion: Can somone give me one or more sentences using 'acabar de'?
OP went fishing in Google Translate for the vocabulary he needed to write a sentence, which was supposed to demonstrate the usage of a particular expression which, as the answerer wrote, "is semantically dubious" -- and I'm not even sure for what purpose. To create a practice exercise for himself? To create a lesson for other students?
Regardless, he's going about things ass backwards, and I don't think we should support that by contributing answers.
If OP wants to know whether "acabar de" can be used in the way he's imagining, that is a question we can answer, and then I think it's fine to contribute answers.
If OP is finding that dictionaries and other resources are not sufficient to figure out a good way of expressing the concept of "rude/impolite" in Spanish, he can show what he has attempted so far, and ask for help; and then we can help him.
I know we're a small site hoping to bring in more participants, but let's be a little choosier about the questions we answer. Or at least let's edit the question into better shape before we answer.
(I wish there were a "pregunta-de-mala-calidad" tag.)