Shithole should work.

In Germany: if you're an estate agent you'd call it an Eigentumswohnung but most people aren't show offs so they just call it a Wohnung.

I own and live in a condo, and sometimes call it an apartment., because condo sounds bougie to me. Especially because I happen to know the building was built as apartments and converted later. Lots of people rent condos as well, so they have a landlord, the owner of the unit. Anyway, you can usually say apartment to give the idea it's a multifamily dwelling.

It's a flat if it's one floor, owned or rented. 'Flat' is also easier to write, say, and spell too.