Slang verb usually meaning to commit an act which will result in a long prison sentence or even death. Most commonly used in NYC, though not exclusively. One who crashes out can also be called a 'crash dummy'.
Person 1: I really wanna kill this opp over there.
Person 2: Nah, it's broad daylight; don't crash out over some petty beef.
Person 1: You right, Ion wanna be no crash dummy.
When in prison, someone turns you in for an offense (either real or fictional) in order to get you put in seg (administrative segregation). Usually done as an act of retribution.
Michele fucked Patty's bitch and Patty found out, so Michele knew a cross out by Patty or one her friends was coming that could land her in seg for 60 days.
Chemist/biologist slang for "precipitate" (as in "to precipitate from solution"). Can be used as a verb or a noun. Like most technical slang, it is used more often in the field than the formal term.
Occasionally mixed up with the different but related term "salt out".
n. That flask should be kept on heat until all the reactants are in to avoid premature crash out.
v. If you don't drop in more DMSO when you make the diluted solution, your compound's going to crash out.
v. "Salting out" a protein is increasing salt concentration in a solution until the desired protein crashes out.