Sentence:  The criminals could never predict if a Big Polis would be feeling his collar at any time. The beat Polis knew every nook and cranny on his beat, (he knew every <WSD>crook and nanny</WSD> too). No one, but no one, would dare to call a Big Polis, "the filth", or similar name in those days. 
Meaning of the word marked with <WSD> tags:  Average person or people.