Synonymous with the commonly used phrase, "What's up"? Used by one who is looking to find an agenda of
recent events.
The phrase "What's crack-a-lackin'?" originated in
ghettos, and was used by
thugs and gangsters to find out the news about any recent crimes committed in the area ('crack-a-lack' is derived from sound a gun makes when fired).
Guy 1: "Ay yo Tito, what's crack-a-lackin'?"
Guy 2: "Nothin
my nig, but I heard that JoJo got whacked last night at da club."
Guy 1: "Fo real yo? I heard they was
poppin' off, but I ain't know JoJo was
whilin like that!"