A nice dinner, generally fairly greasy and unhealthy but lovely nonetheless. What you might have in the Lobster Pot or Superdine after drinking the shit out of it. Curry Cheese Battered Sausage definitely falls into that category, as does a Garlic Cheese Chip.
I was so scagged so I didn't get into college til lunchtime so for breakfast I had a filthy Chicken Curry in the Stables.
A group of girls that one would generally agree are filthy or dirty in a sexual sense. May not be a negative even though the word implies a negative connotation. Could be a sarcastic way to say that a girl is hot and (you hope) dirty.