In what context did you find this phrase? Have you looked up sharpshooter and streetwalker to see if they have a definition that fits it?
Always cite the author (when known) and source of every text you post here. It's a firm rule of the forum. Please respond to this post with that information.
You've done that before, sasibhaskar—in your post about an objective dog—asked about a short phrase in isolation and putting us to the trouble of requesting the source and author before we can give you a meaningful response.