In a Pickwickian sense. An insult whitewashed. Mr. Pickwick accused Mr. Blotton of acting in “a vile and calumnious manner,” whereupon Mr. Blotton retorted by calling Mr. Pickwick “a humbug.” It finally was made to appear that both had used the offensive words only in a Pickwickian sense, and that each had, in fact, the highest regard and esteem for the other. So the affront was adjusted, and both were satisfied.
“Lawyers and politicians daily abuse each other in a Pickwickian sense.” —Bowditch.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Pickwickian from Infoplease: