Learn English – What kind of rhetoric is “The computer runs as fast as a rocket.”

An academic or pseudo-intellectual who uses convoluted phrases in order to intimidate the lay person, ostentate his or her position, and possibly, disguise the fact that they have nothing of any importance to say, is commonly called a windbag.

If you are looking for a fancier term for verbosity, I present pressologia

Perissology means using more words than necessary to explain one’s meaning, a pleonasm. Since perissology is three letters longer than pleonasm but means the same, you may argue it’s an example of the related habit of using long words when shorter ones will do.

In A Dictionary of Literary Devices: Gradus, A-Z by Bernard Marie Dupriez, we learn that it is indeed a tactic, a form of strategy for filling an empty page or moments of silence. However, as I understand it, it needn't be incomprehensible.

pressology is one of the principle devices used by the media in their production of filler or padding

A similar rhetorical device is battology, which Richard Nordquist defines as "A rhetorical term for needless and tiresome repetition in speaking or writing". It reminds me of the Italian verb battere and gerund form battendo, which can be translated to hammering, and the English idiom to beat around the bush when someone is deliberately being evasive or unclear.

But the best word I found, and one which didn't have me scrambling for my dictionary, is the pejorative and informal term academese.

Academese is characteristic of academicians who are writing for a highly specialized but limited audience, or who have a limited grasp of how to make their arguments clearly and specifically" (Garner's Modern American Usage, 2009).

A further example of academese is provided here, the words which I have placed in bold are the academese expressions.

Vernacular Equivalents to Academese

"[E]ffective academic writing tends to be bilingual (or 'diglossial'), making its point in Academese and then making it again in the vernacular, a repetition that, interestingly, alters the meaning. Here is an example of such bilingualism from a review of a book on evolutionary biology by a professor of ecology and evolution, Jerry A. Coyne. Coyne is explaining the theory that males are biologically wired to compete for females. Coyne makes his point both in Academese, which I italicize, and in the vernacular, staging a dialogue in the text between the writer's (and the reader's) academic self and his 'lay' self: 'It is this internecine male competitiveness that is assumed to have driven not only the evolution of increased male body size (on average, bigger is better in a physical contest), but also of hormonally mediated male aggression (there is no use being the biggest guy on the block if you are a wallflower).'

^{source: Gerald Graff, Clueless in Academe: How Schooling Obscures the Life of the Mind. Yale Univ. Press, 2003}

I believe that the closest one will come is, indeed, catachetical, or catechetic - the 3rd meaning given in the Oxford English Reference dictionary : "consisting of or proceeding by question and answer." Unfortunately, there is no mention of rhetoric here. Since there actually appears to BE no word describing exactly that which you seek, may I suggest a new word? Catachrhetoral?...(catachrhetoralism.)