"Attero Dominatus" is the title of an album and song by the band Sabaton. According to this article, which does not cite any source, it means "destroy tyranny", according to this Wikipedia page it means "I destroy tyrannies". The band has not provided an official translation of the song. What is the correct translation?
The official translation is off. I am rather annoyed that people put time and money into projects like this but do not take more care with the translation of a name — but I refrain from ranting further.
Let us start with the verb atterere. It means literally something like "to rub against", and it also has the sense "to destroy". Perhaps "to destroy by rubbing" is a good overall translation. Check the dictionary entry in Lewis and Short for more detail. There would be far better verbs for destroying tyranny, but asking for them should be taken to a separate question. If we pick the translation "to destroy" for atterere, the form attero means indeed "I destroy".
I see two ways to parse dominatus:
It can be the noun dominatus, which means many kinds of rule or sovereignty. It does cover tyranny as well, but I would not recognize it as the principal meaning. In the context of the short sentence attero dominatus, it appears to be in the plural accusative, which indeed happens to look like the singular nominative (the basic form given in a dictionary) for this word. This leads to translation possibilities like these:
I weaken/destroy sovereignties.
I wear out the rules. (≈ I defy the law and break it slowly.)
It can be a participle of the verb dominari, "to rule". This leads to translation possibilities like these:
After having been a ruler I rub something.
I rule and destroy.
As always, there is no unique correct translation without more precise context. And I admit that some of the suggested translations are quite nonsensical, but I would argue that so is the original phrase, to some extent at least. The official translation is a possible direction, but the choices of words look unnatural to me.