the adjective is lexiphanic, the noun is lexiphanicism:

lexiphanic \Lex`i*phan"ic\ (l[e^]ks`[i^]*f[a^]n"[i^]k), a. [Gr. lexifa`nis a phrase monger; le`xis speech + fai`nein to show.] Using, or interlarded with, pretentious words; bombastic; as, a lexiphanic writer or speaker; lexiphanic writing.

and now I'm going to once again suggest that queries such as this can be easily satisfied by using http://www.onelook.com/ as the first resource.

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