Yeah, we just used a twenty-dollar word to describe Dickens’s style in Oliver Twist, but it’s appropriate because it’s just the kind of word he would use. Basically, we just mean that the narrator talks around the point a lot (that’s what "periphrastic" actually means), and describes things in gory detail... without coming right out and saying what he means.
For example, at the start of Book I, Chapter Thirteen, Dickens describes the Dodger and Charley’s theft of Mr. Brownlow’s wallet as "an illegal conveyance of Mr. Brownlow’s personal property" (12.1). Part of the effect of that periphrastic language to show how jargon can be used to justify almost anything. This is dangerous; Dickens seems to maintain that you should call a thief a thief, and not try to gloss it over.