SHOOT UP

v. 1. To grow quickly. Billy had always been a small boy, but when he was thirteen years old he began to shoot up. 2. To arise suddenly. As we watched, flames shot up from the roof of the barn. 3. informal To shoot or shoot at recklessly; shoot and hurt badly. The cowboys got drunk and shot up the bar room. The soldier was shot up very badly. 4. To take drugs by injection. A heroin addict will shoot up as often as he can.