1. To increase sharply. Please stop jacking up the volume on the TV. I can barely hear myself think.

2. To raise something through the use of a jack, a simple machine used to lift things. We'll need to jack up the car before we can change this tire.

3. To stimulate, excite, or motivate, often but not always through the use of drugs. In this usage, a noun or pronoun is sometimes used between "jack" and "up." By the way he was flitting around, you could tell the guy was jacked up on something. This soundtrack jacks me up so much when I'm working out.

4. To inflict damage upon, physically or otherwise. In this usage, a noun or pronoun is sometimes used between "jack" and "up." Yikes, that car wash really jacked up your car's exterior. I'm not going to lie, that horror movie jacked me up for weeks.