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.
1. slang Extremely excited, enthusiastic, or motivated. Everyone at the company is really jacked to show the world what we've been working on for the last three years. The coach got the team jacked up ahead of the big championship game.
2. slang Having very large and well-defined muscles. Tom used to be a skinny little dude, but he spent the summer getting jacked. With my simple workout routine, you won't need expensive supplements or endless time at the gym to be totally jacked up!
See also: jacked
1. and jacked mod. excited. I was so jacked I almost passed out. Don was really jacked up about the election.
2. mod. arrested. (Underworld.) What time did Sam get himself jacked up?
3. mod. upset; stressed. I was really jacked up by the bad news.
4. mod. high on drugs. He’s jacked up, and he may have ODed.