In chapter four, Nick travels into New York City with Jay Gatsby, where the two neighbors have lunch with Gatsby's suspicious business partner, Meyer Wolfsheim. When Nick is initially introduced to Wolfsheim, Wolfsheim ignores him and continues to carry on a rather serious conversation with Gatsby. After Meyer Wolfsheim comments on the brutal murder of his friend, Rosy Rosenthal, at the old Metropole, he turns to Nick and says,

I understand you’re looking for a business gonnegtion. (Fitzgerald, 76)

Meyer's comment to Nick is presumably a business proposition to work for him in some particular area of the criminal underground. Essentially, Meyer Wolfsheim believes that Nick is looking for a job and is willing to work for him. Before Mr. Wolfsheim can elaborate further on the business opportunity, Gatsby intervenes and mentions that Nick is not the man Meyer assumes he is but is simply a friend. As the lunch continues, Nick learns that Wolfsheim is a prominent gambler who fixed the 1919 World Series and successfully avoided the law. Nick's introduction to the shady Meyer Wolfsheim reveals that Jay Gatsby is somehow connected to the criminal underground, which gives credence to the rumors that he is involved in the illegal bootlegging industry.

In Chapter Four when introduced to Nick Carraway, Meyer Wolfscheim assumes that Nick is looking for "a business gonnection," but Gatsby tells him that he has mistaken Nick for someone else and that he is just a friend. 

This mention of a business connection, a euphemism for a job with the underworld, informs Nick that Jay Gatsby is not the gentleman that he portrayed himself as earlier in this same chapter. In fact, this association with Meyer Wolfscheim, a man who has human molars for cufflinks, and who is rumored to have been involved in the "fixing" of the 1919 World Series, certainly casts doubts upon Gatsby's character. Further, Nick begins to think that the rumors of Gatsby's connection with bootlegging may be true because when Nick asks Gatsby why Wolfscheim is not in jail for the fraudulent scheme of "playing with the faith of fifty million people," Jay Gatsby replies nonchalantly, "They can't get him, old sport. He's a smart man."