a little like the word 'bad' when it first came to fashion in the early 90s, (late 80s), murky's meaning is twofold. It is the new word for "shady", which basically means something is sly - a sneaky manoevre on some filth (a chick) can be sly, or a devious burglar could be sly.
that shizzle was murky, you proper murkied on that filth yo. Word to dat murkiness my nizzle. sheeit.