Slang for Heroin. It comes from the fact, that Heroin is also brown. Originally used in the Libertines song "What Katie Did".
Can also mean, that you're feeling sad or moody. Reference to the fact, that people feel poor, when they come off the Heroin.
1:Hey dude. I'm going to visit Sally Brown tonight. It's going to be craxy

2:
Guy 1: How are you?
Guy 2; I'm not good. I fell like Sally Brown has left me.
by Jakob Orbesen April 9, 2008
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