|: : Squatter is the word.
: In NYC, a squatter is someone who lives in a vacant or abandoned building rent-free. And the city is doing away with them and as a result we have more homeless living on the streets instead.
In German, we have the beautiful word "Hausbesetzer" for this. There were times, when there were a lot of them. I haven't heard of them for years now, though. I think, I even learnt the word squatter in school. Quadder always looks to me similar to squatter.