Welsh English is lush, it is. Valleys slang is its own beast, musical, warm, and peppered with Welsh-language borrowings that give it a rhythm you won't find anywhere else, like.
Lush
Gorgeous, lovely, absolutely fantastic. In Wales, "lush" covers everything from a beautiful sunset to a great curry. It's the Swiss Army knife of Welsh compliments.
Tidy
Great, excellent, spot on. Nothing to do with cleaning, in Wales, "tidy" means everything is exactly as it should be. It's approval, satisfaction, and admiration rolled into one.
Tampin
Absolutely fuming, properly angry, ready to blow. When a Welsh person is tampin, you best give them space. It's rage with a musical accent.
Cwtch
A cuddle, a hug, a safe place. Pronounced "kutch." It's more than a hug, it's that feeling of being wrapped up safe and warm. There's no English equivalent because English isn't soft enough.
Tump
To knock over, to tip something. Uniquely Welsh English, you tump a glass, tump a chair, tump yourself over. The rest of Britain has no idea this word exists and that's their loss.
Caulk
To sleep, to nap, to have a kip. In Welsh English, "caulking" is having a lie-down. It sounds like a DIY term but in Wales it's the verb for catching some much-needed rest.
Twp
Stupid, daft, a bit dim. From the Welsh language, "twp" (say "toop") is the gentle Welsh way of calling someone a bit thick. It's an insult wrapped in a Welsh accent, which makes it almost cute.