1. noun In baseball or softball, an especially fast pitch. Watch out for their new pitcher—I hear her speedball is incredibly fast.

2. noun, slang A mixture of cocaine and heroin (or, less commonly, morphine), which is inhaled through the nose or injected intravenously. I knew I was at the wrong party when I saw people doing speedballs.

3. verb, slang To inhale or inject such a mixture. When I walked into a room full of people speedballing, I knew I needed to get out of that party.