1. To grow, rise, or increase very quickly or dramatically. Wow, you kids have really shot up since you were here last summer! Stocks in the company shot up when they announced the impressive sales figures for their latest product. Rental prices have started shooting up in this area over the last couple of years.

2. slang To use recreational drugs intravenously, especially heroin. This is a nasty part of town—you can find someone shooting up around just about every corner.

3. To attack a place and/or the people there with gunfire. The gang of criminals shot up the sheriff's town in retribution for their leader's arrest. A deranged gunman began shooting up a shopping mall earlier today.

4. To shoot someone or something repeatedly. In this usage, a noun or pronoun can be used between "shoot" and "up." The suspect was wielding a knife, but police shot him up before he could attack anyone. The kids took their dad's handgun and started shooting up the side of the old barn.