A pun is most often seen as humorous. However, in this novel, the narrator uses dark or solemn puns like "Out-With" and "Fury" to convey certain meanings. Bruno is simply mispronouncing the real words, but the author is clearly asking the reader to consider a double meaning to these words. Discuss the use of this wordplay as a literary device. What is the narrator trying to convey to the reader? How do these words further communicate the horror of the situation?

The horror of Bruno's situation is all the more intense because he has no idea of what's going on around him. The accidental puns he uses are a reflection of his total ignorance, his naivety. They separate him from what's really happening, keeping him cocooned in his own little world from which the horrors of Auschwitz and the leading role played by his own father in perpetuating those horrors have been excluded.
The Nazis themselves often abused language, using euphemisms like "resettlement" to describe the mass transportation and murder of millions of Jews across Europe. But the difference is that they knew exactly what they were doing, whereas Bruno's idiosyncratic use of language is a reflection of his relative youth and immaturity. He has an excuse for being ignorant of what's going on around him that the adults simply do not have. Even as he mispronounces Auschwitz and Führer, Bruno still manages to express something of the truth of what those terrible words represent in a way that the adults in his life never could.

Bruno is an innocent child who does not understand the complicated world around him. Boyne hammers this point home by showing that Bruno doesn't even understand some of the words used by the adults to describe the Nazi lifestyle. In using these words, Boyne is clearly stating Bruno's misunderstanding while also creating a social commentary on what these ideas actually represent.
Bruno refers to Auschwitz as "Out-With." Neither Bruno nor Gretel can pronounce the word, and when Bruno asks Gretel why it has that name, she says, "Out with the people who lived here before us, I expect." It's a very on-the-nose moment where the reader can see that Auschwitz, a Nazi concentration camp, is a place where people are taken to get them out of the way of the other citizens of Germany.
"Fury" is the title that Bruno assigns to Adolf Hitler (known as the Führer). Like "Out-With," "Fury" is a direct explanation of how to feel about Hitler and evokes the fury of an angry dictator whose sole goal was to exude power and create a following that would literally kill for him.