Plagiarism is copy & paste without source link. It is a most recognized type of plagiarsim. There are some other types and people can think that they are smart enough to avoid plagiarism but still steal idea of the others. They are wrong because what is considered as plagiarism on the forum is not limited to copy & paste without source link.
Plagiarism is what gets people permabanned, not just copying. Plagiarism is copying with the intent of passing the work off as your own. In essentially all cases, plagiarism deserves a permaban because it usually proves definitively that the person is here for the wrong reasons: to fill up space in order to get paid, not to actually discuss or contribute. If someone was able to convince us that they were plagiarizing just to eg. impress people rather than to fill up space, then a lesser ban of a few months might instead be warranted. But this has never happened AFAICR. (Arguments based on plausible deniability aren't going to work; we don't need to prove that you had the motive we see in your actions.)
Plagiarism: If you copy some text from somewhere, then you should have a good reason for it, and you must link to the source. Doing otherwise is plagiarism. Changing a few words around doesn't matter. If we find that you plagiarized, then you absolutely will be permanently banned, even if we find it years after you did it.
For the OP question, I think it is similar to what was discussed in the following thread
New sort of plagiarism. However, the case raised by OP is different and 'looks' better, harder to be detected. It was translated manually, not by Google translate. Maybe the poster did
text-spinning which is another type of plagiarism