What “Gweh” means
Gweh means "go away". It can send a person off or, in "gweh wid dat", dismiss an idea entirely. Depending on tone it can be playful teasing or a serious brush-off.
Examples
Gweh!
Go away!
Cho, gweh wid dat!
Ugh, to hell with that!
How to use it
Common in casual speech. Between friends it's often a laughing "get out of here"; said sharply, it's rude, so be careful using it with elders or strangers.