high-flown

/ˌhaɪ ˌˈfloʊn/

A person is considered high-flown if he tries to sound smarter or fancier than he really is.

The adjective high-flown particularly comes in handy when you're describing overblown, pretentious writing. You can also describe overly lofty plans as high-flown: "The six year-old's intention to build a tree house with wall-to-wall carpeting, electric lights, and plumbing seemed a little high-flown to me."

Definitions of high-flown

1. adjective

   pretentious (especially with regard to language or ideals)
   “high-flown talk of preserving the moral tone of the school”

   synonyms: high-sounding, inflated

   pretentious

   making claim to or creating an appearance of (often undeserved) importance or distinction
2. adjective

   of high moral or intellectual value; elevated in nature or style
   “"argue in terms of high-flown ideals"- Oliver Franks”

   synonyms: elevated, exalted, grand, high-minded, idealistic, lofty, noble-minded, rarefied, rarified, sublime

   noble

   having or showing or indicative of high or elevated character