Really : adv. (word coming from cow).
Very ; a lot (funny, harsh, damn).
Really good: very good.
I'm really thirsty : very thirsty.
You're really stupid : you are really stupid: idiot.
He's really aged: a lot.
He answered me really harshly: very harshly.
She's really good. He really helps us.
In a cowardly way: badly, harshly.