Depending on context this can mean either something, or someone who is:
1) Way far out there; extremelyfucked up; an idiot OR,
2) beyond greatness; supercool; the bomb; very sexy.
EXAMPLE 1
"Here comes that dumbass, Dice'n Tyson. Man, he is MADWHACK off the track!"
EXAMPLE 2 "Yo, dawg, check it out. This station's playin' some MADWHACK remix beats tonight.
A word is used to express the impossible amount of "Whack" a certain person/place/situation/thing is; It was first used by Eloy Martinez-Aguilar when his teacher assigned 63 problems of geometry as overnight homework. The word is a pun on the name Marowak, the evolution of the Pokemon Cubone.
Demolished, destroyed, or otherwise just plain torn up. Can be used to descried things, actions, or people. Originates from Lumberton NC, where it is a slang term from Lumbee-English.