1.
If something shoots up, it grows or increases very quickly.
Sales shot up by 9% last month...
The fair market value of the property shot up.
PHRASAL VERB: V P by/to n, V P
2.
If a drug addict shoots up, they inject a quantity of drugs into their body. (INFORMAL)
Drug addicts ~ in the back alleys...
We shot up heroin in the playground.
PHRASAL VERB: V P, V P n (not pron)