Mr. Blotton had no hesitation in saying, that he had not–he had used the word in its Pickwickian sense. (Hear, hear.) He was bound to acknowledge, that, personally, he entertained the highest regard and esteem for the honourable gentleman; he had merely considered him a humbug in a Pickwickian point of view. (Hear, hear.)
If the humor here is obscure, you may care to note the very helpful footnote in the Penguin edition of the Pickwick Papers:
A notorious parliamentary slanging match between Brougham and Canning in April 1823 was resolved by Brougham’s plea that his accusations had been directed at Canning’s official, not his private, character. Parliamentarians of the 1830s took Dicken’s jibe to heart. In 1838, one MP remarked that this ‘single stroke’ of Dicken’s pen had killed off the old excuse that calumnies ‘were only meant to apply “in a parliamentary sense”‘ (Fraser’s Magazine, October 1838).