“[Wickham had] vicious propensities… [and] his life was a life of idleness and dissipation.” From Mr. Darcy’s letter to Elizabeth.
To answer that question, we have to list those things that are known about him.
He went into debt. These debts were both gambling debts and debts to merchants. The gambling debts were debts of honor, and thus not legally recoverable. The debts to the merchants in Meryton and Brighton were much more serious in Jane Austen’s time than today, because he could go to debtor prison.
He slandered Mr. Darcy. He certainly was guilty of that, and Darcy could have sued him for damages. Of course, Wickham didn’t have any money to pay Darcy.
He tried to elope with a fifteen year old heiress. This looks worse from a modern perspective than from the time. Mr. Wickham and Georgiana Darcy could legally marry in Scotland. He also had the consent of the person who was in charge of Georgiana. Mrs. Younge wasn’t Georgiana’s legal guardian, but was entrusted to her care. Her encouragement of the elopement gave Wickham some legitimacy.
He ran off with a sixteen year old. Again, this was less serious in his day than now. I don’t claim to know the law on this issue, but the fact that Mr. Darcy couldn’t get Lydia Bennet to leave Wickham suggests there were no legal issues here. Also, Lydia’s mother was happy with the marriage. The fact that the Bennets’ neighbors accepted Lydia and Wickham once they were married suggests that they didn’t consider Wickham too evil for this act.
As villains go, Wickham is very mild. Darcy said he had vicious propensities, but at the time Jane Austen wrote, “vicious” meant “immoral, corrupt. The word then did not have the connotations of ferocity or aggression that it has now.” [The Annotated Pride and Prejudice, edited by David M. Shapard, 2004, page 369.] It is easy to believe that he was guilty of “idleness and dissipation,” but that came from a man who hated him. A less prejudiced observer, Mrs. Reynolds, called him very wild. Wickham certainly wasn’t a good man, but calling him evil does not seem to be justified.
…except that he caused pain to our favorite fictional characters, Darcy and Elizabeth.
