A knock is someone who is a fiend for drugs of any kind. There can be weed knocks, coke knocks, pill knocks, etc... Also refers to when someone exhibits "knockish" behavior, i.e. fiending for drugs or just acting square. (see square) The word knock is derived from the "knock" of a fiend knocking on the door looking for drugs.
I was left with the decision of whether to bust some knocks and make that money or just kick it with these females.