Essentially means being wise to
something, “in the know”, and generally understanding how things
work. To “know the koo” is the same as to “know the score” in a situation. You can use it as “knowing the koo” or as being “koo’d up”. So, in
London you might hear something like:
“You shouldn’t say stuff
like that around here! You need to be more koo’
d up!”
“Just follow him, he knows the koo.”