Saw this word on a Jodel. I googled it and it said that it means American. Is this like a word Germans use to call Americans? Is it in any way impolite?
No insult, but an informal word. Its neither negative nor positive.
Many names get abbreviated by using the "beginning" of the word and adding an i sound at the end. Thats what basically happend with the word Amerikaner/in.
it's a slightly degrading/mocking word for americans, but I think it can also be neutral. maybe like "gringo" in spanish.
This is my consistent with my experience. My wife and I were "greeted" by a handful of German locals upon coming out of a beer hall in Munich. They made the connection between us being Amis and how that reminded them of Ants (Ameisen). I don't think they meant disrespect, but only they know for sure.