What does it mean to be pickwickian?Not "pickwickian syndrome" (this is mostly what I have been finding), but what it means when it is referenced as a literary allusion.
In the literary sense, "Pickwickian" comes from Charles Dickens' Pickwick Papers. Several meanings of the word actually derive directly from this novel.
One character in the novel, Samuel Pickwick, is known for his simplicity and kindness. In this way, as an adjective, pickwickian means naive, generous, or innocent.
Mr. Pickwick and another character, Mr. Blotton, frequently call each other seemingly offensive names. In reality, the two actually have very high regard for one another and only insult each other in a pickwickian sense. In this way, the word means not literal.
Finally, pickwickian syndrome, which is a scientific term referring to symptoms of extreme obesity, shallow breathing, and fatigue, come also from the novel, but not from the main character. This meaning of pickwickian comes from the character Fat Joe, but clearly refers simply to the title of the book.