1. not working properly or as intended.
2. having used a large quantity of speed, cocaine, or other amphetamine.
3. cut or lacerated by means of a make-shift knife or blade. see SKIV
4. In generally poor or injured condition.
sense "1": "This is so JACKED UP! She said she'd be here at eight!"
sense "4": "I want to play, but my shoulder's still JACKED UP from last weekend.
1. music: to play distorted electric lead guitar in a manner which is at once so extremely cogent and rapid that listener experiences the sensation that the production of the sound should be impossible or nearly impossible.
2. surfing: performing a series of cutbacks requiring seemingly impossible adeptness.
3. going every-which-way at once
Garcia was SHREDING so hard in the middle of Shakedown, i thought my head would explode.