Some of those terms might seem weird. How can a style be "fluid" after all? First off, verbose is a fancy way of saying "wordy," which Eliot definitely is. This book is over five hundred pages long, after all. Eliot’s sentences are often extremely long and she uses lots of fun punctuation (dashes, semi-colons) to avoid using periods. Here’s an example of a pretty lengthy spiel:
Snow lay on the croft and river-bank in undulations softer than the limbs of infancy; it lay with the neatliest finished border on every sloping roof, making the dark-red gables stand out with a new depth of colour; it weighed heavily on the laurels and fir-trees till it fell from them with a shuddering sound; it clothed the rough turnip-field. (2.2.2)
OK, we’re taking a break at the turnip-field. Aside from being long (which it is) this sentence is also full of vivid imagery, metaphors (like "limbs of infancy"), sensory detail (like descriptions of sounds and colors), and detailed descriptions. Eliot is definitely using all these words for a reason, and her sentences do a lot of work. What’s fantastic about this sentence is how it manages to make a thematic statement without being overly obvious about it. Here’s a sample of what comes after the turnip-field:
[T]he gates were all blocked up with the sloping drifts, and here and there a disregarded four-footed beast stood as if petrified [...] the heavens too were one still pale cloud - no sound or motion in anything but the dark river, that flowed and moaned like an unresting sorrow. (2.2.2)
Within the span of one (long) sentence, Eliot shifts from romantic imagery to much more negative images, like the river "moaning" in "sorrow." Stylistically, this sentence changes as it progresses too. The beginning has a lot of anaphoras, which is a fancy word meaning that each new phrase begins the same way: in this case with "it, past-tense verb." The end of the sentence abandons this device. Basically, Eliot undermines the romantic view of the snow by elaborating on the reality of a cold, harsh winter. This ties in one of the book’s major themes: don’t judge things too quickly or make assumptions.
It may seem like "verbose" and "detailed" are the same thing. There is a distinction, though. Eliot’s sentences are very long and wordy, hence the "verbose" style. But Eliot also uses a lot of these long and wordy sentences to describe people and events and places, hence the "detailed" style. Detailed here is sort of commenting on entire paragraphs and chapters, which give us a lot of information about everything that is going on in the book. We are very rarely left to make assumptions about things for ourselves. Here’s an example where the narrator gives us not only information but also interpretation:
And yet – how was it that she was now and then conscious of a certain dim background of relief in the forced separation from Philip? Surely it was only because the sense of a deliverance from concealment was welcome at any cost? (5.5.90)
Even though Maggie doesn’t admit it to herself, the narrator gives us some hints, through the use of leading questions, that Maggie is actually glad to be away from Philip because she isn’t really in love with him.
All of this detail and wordiness often lead to a rather repetitive style. Repetitive isn’t meant in a bad way, though. Rather, the style is repetitive in order to hammer home certain themes and to highlight the importance of certain conversations and events. We get a lot of repeated conversations in this book. For instance, Maggie and Philip debate the pros and cons of Maggie’s self-sacrificial nature. Stephen and Maggie also have a lot of recurring debates revolving around the question of whether or not they should pursue a relationship. This is true to life really – if you have something really important to discuss with a friend, or are having a disagreement, you wouldn’t just discuss things one time, right?
Finally, we have fluid. Basically, all of the other stylistic traits (repetition, wordiness, lengthy sentences, lots of detail) combine to create a very fluid style. Fluid here means that the style "flows" and that all the different aspects of the narrative fit together well. For instance, we don’t have a lot of dramatic breaks or jarring interruptions here. Even when the narrator goes off on a tangent (usually at the end or beginning of a chapter), the discussion flows directly out of a scene or directly into an upcoming scene. Even the weirdest chapter in the whole book, "A Variation of Protestantism Unknown to Bossuet," is not totally random: it’s actually setting up Maggie’s upcoming religious experience. The places where we do have breaks in the narrative, like a major time jump, are notable for their scarcity. And even the time jumps themselves aren’t really highlighted. The breaks are sort of buried in the rest of the narrative, which continues to flow along with lots of words, descriptions, and repeated conversations. It’s also rather fitting that this book stylistically flows, since water imagery and themes play such a major role in it.