Nah ah
It’s like saying ‘obviously no’ but with more attitude. Like when someone tries to trick you and you know they’re full of crap.
He said he would clean his room. I said, ‘Nah ah, you’re just saying that.’
She told me she would eat all the cake. I said, ‘Nah ah, you’re going to eat the last piece.’
He said he would do his homework. I said, ‘Nah ah, you’re going to fail.’