Pronounced with a short "o" as ion "pot". In the Upper Colonies, grotty is applied to nearly anything that isn't very pleasant. "Geez, look at that grotty park bench. It's covered with birdshit!" or "Look at the grotty weather .. it's chucking it down again." Or it can be applied to how you feel ... "Bloody cold. I've been feeling grotty for days.". And I've always fondly imagined it came directly from "grotesque".