look up any word, like wcw:
 
1.
A Southern United States phrase; it usually shows disgust or suprise with a situation or person.

Because the phrase tends to be used by itself, many people in the North US who hear it think that the speaker has not finished their sentence.
A, Southerner: "That Joel; I tell you what."
*a few seconds pass*
B, Northerner: "... What?"
A, Southerner: "I just TOLD you!"
by Leilani_h June 04, 2005
 
2.
1. To kick someone in the face
1. I'm gonna tell you what!
by Jesus March 18, 2005